def image_search_async(custom_config, query, accept_language:nil, user_agent:nil, client_id:nil, client_ip:nil, location:nil, aspect:nil, color:nil, country_code:nil, count:nil, freshness:nil, height:nil, id:nil, image_content:nil, image_type:nil, license:nil, market:nil, max_file_size:nil, max_height:nil, max_width:nil, min_file_size:nil, min_height:nil, min_width:nil, offset:nil, safe_search:nil, size:nil, set_lang:nil, width:nil, custom_headers:nil)
      fail ArgumentError, '@client.endpoint is nil' if @client.endpoint.nil?
      x_bing_apis_sdk = 'true'
      fail ArgumentError, 'custom_config is nil' if custom_config.nil?
      fail ArgumentError, 'query is nil' if query.nil?


      request_headers = {}
      request_headers['Content-Type'] = 'application/json; charset=utf-8'

      # Set Headers
      request_headers['x-ms-client-request-id'] = SecureRandom.uuid
      request_headers['X-BingApis-SDK'] = x_bing_apis_sdk unless x_bing_apis_sdk.nil?
      request_headers['Accept-Language'] = accept_language unless accept_language.nil?
      request_headers['User-Agent'] = user_agent unless user_agent.nil?
      request_headers['X-MSEdge-ClientID'] = client_id unless client_id.nil?
      request_headers['X-MSEdge-ClientIP'] = client_ip unless client_ip.nil?
      request_headers['X-Search-Location'] = location unless location.nil?
      path_template = 'images/search'

      request_url = @base_url || @client.base_url
    request_url = request_url.gsub('{Endpoint}', @client.endpoint)

      options = {
          middlewares: [[MsRest::RetryPolicyMiddleware, times: 3, retry: 0.02], [:cookie_jar]],
          query_params: {'customConfig' => custom_config,'aspect' => aspect,'color' => color,'cc' => country_code,'count' => count,'freshness' => freshness,'height' => height,'id' => id,'imageContent' => image_content,'imageType' => image_type,'license' => license,'mkt' => market,'maxFileSize' => max_file_size,'maxHeight' => max_height,'maxWidth' => max_width,'minFileSize' => min_file_size,'minHeight' => min_height,'minWidth' => min_width,'offset' => offset,'q' => query,'safeSearch' => safe_search,'size' => size,'setLang' => set_lang,'width' => width},
          headers: request_headers.merge(custom_headers || {}),
          base_url: request_url
      }
      promise = @client.make_request_async(:get, path_template, options)

      promise = promise.then do |result|
        http_response = result.response
        status_code = http_response.status
        response_content = http_response.body
        unless status_code == 200
          error_model = JSON.load(response_content)
          fail MsRest::HttpOperationError.new(result.request, http_response, error_model)
        end

        result.request_id = http_response['x-ms-request-id'] unless http_response['x-ms-request-id'].nil?
        # Deserialize Response
        if status_code == 200
          begin
            parsed_response = response_content.to_s.empty? ? nil : JSON.load(response_content)
            result_mapper = Azure::CognitiveServices::Customimagesearch::V1_0::Models::Images.mapper()
            result.body = @client.deserialize(result_mapper, parsed_response)
          rescue Exception => e
            fail MsRest::DeserializationError.new('Error occurred in deserializing the response', e.message, e.backtrace, result)
          end
        end

        result
      end

      promise.execute
    end
def image_search_async(custom_config, query, accept_language:nil, user_agent:nil, client_id:nil, client_ip:nil, location:nil, aspect:nil, color:nil, country_code:nil, count:nil, freshness:nil, height:nil, id:nil, image_content:nil, image_type:nil, license:nil, market:nil, max_file_size:nil, max_height:nil, max_width:nil, min_file_size:nil, min_height:nil, min_width:nil, offset:nil, safe_search:nil, size:nil, set_lang:nil, width:nil, custom_headers:nil)
      fail ArgumentError, '@client.endpoint is nil' if @client.endpoint.nil?
      x_bing_apis_sdk = 'true'
      fail ArgumentError, 'custom_config is nil' if custom_config.nil?
      fail ArgumentError, 'query is nil' if query.nil?


      request_headers = {}
      request_headers['Content-Type'] = 'application/json; charset=utf-8'

      # Set Headers
      request_headers['x-ms-client-request-id'] = SecureRandom.uuid
      request_headers['X-BingApis-SDK'] = x_bing_apis_sdk unless x_bing_apis_sdk.nil?
      request_headers['Accept-Language'] = accept_language unless accept_language.nil?
      request_headers['User-Agent'] = user_agent unless user_agent.nil?
      request_headers['X-MSEdge-ClientID'] = client_id unless client_id.nil?
      request_headers['X-MSEdge-ClientIP'] = client_ip unless client_ip.nil?
      request_headers['X-Search-Location'] = location unless location.nil?
      path_template = 'images/search'

      request_url = @base_url || @client.base_url
    request_url = request_url.gsub('{Endpoint}', @client.endpoint)

      options = {
          middlewares: [[MsRest::RetryPolicyMiddleware, times: 3, retry: 0.02], [:cookie_jar]],
          query_params: {'customConfig' => custom_config,'aspect' => aspect,'color' => color,'cc' => country_code,'count' => count,'freshness' => freshness,'height' => height,'id' => id,'imageContent' => image_content,'imageType' => image_type,'license' => license,'mkt' => market,'maxFileSize' => max_file_size,'maxHeight' => max_height,'maxWidth' => max_width,'minFileSize' => min_file_size,'minHeight' => min_height,'minWidth' => min_width,'offset' => offset,'q' => query,'safeSearch' => safe_search,'size' => size,'setLang' => set_lang,'width' => width},
          headers: request_headers.merge(custom_headers || {}),
          base_url: request_url
      }
      promise = @client.make_request_async(:get, path_template, options)

      promise = promise.then do |result|
        http_response = result.response
        status_code = http_response.status
        response_content = http_response.body
        unless status_code == 200
          error_model = JSON.load(response_content)
          fail MsRest::HttpOperationError.new(result.request, http_response, error_model)
        end

        result.request_id = http_response['x-ms-request-id'] unless http_response['x-ms-request-id'].nil?
        # Deserialize Response
        if status_code == 200
          begin
            parsed_response = response_content.to_s.empty? ? nil : JSON.load(response_content)
            result_mapper = Azure::CognitiveServices::Customimagesearch::V1_0::Models::Images.mapper()
            result.body = @client.deserialize(result_mapper, parsed_response)
          rescue Exception => e
            fail MsRest::DeserializationError.new('Error occurred in deserializing the response', e.message, e.backtrace, result)
          end
        end

        result
      end

      promise.execute
    end
The Custom Image Search API lets you send an image search query to Bing and
 get image results found in your custom view of the web.

 @param custom_config [String] The identifier for the custom search
 configuration
 @param query [String] The user's search query term. The term cannot be empty.
 The term may contain [Bing Advanced
 Operators](http://msdn.microsoft.com/library/ff795620.aspx). For example, to
 limit images to a specific domain, use the
 [site:](http://msdn.microsoft.com/library/ff795613.aspx) operator. To help
 improve relevance of an insights query (see
 [insightsToken](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#insightstoken)),
 you should always include the user's query term. Use this parameter only with
 the Image Search API.Do not specify this parameter when calling the Trending
 Images API.
 @param accept_language [String] A comma-delimited list of one or more
 languages to use for user interface strings. The list is in decreasing order
 of preference. For additional information, including expected format, see
 [RFC2616](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html). This
 header and the
 [setLang](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#setlang)
 query parameter are mutually exclusive; do not specify both. If you set this
 header, you must also specify the
 [cc](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#cc)
 query parameter. To determine the market to return results for, Bing uses the
 first supported language it finds from the list and combines it with the cc
 parameter value. If the list does not include a supported language, Bing
 finds the closest language and market that supports the request or it uses an
 aggregated or default market for the results. To determine the market that
 Bing used, see the BingAPIs-Market header. Use this header and the cc query
 parameter only if you specify multiple languages. Otherwise, use the
 [mkt](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#mkt)
 and
 [setLang](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#setlang)
 query parameters. A user interface string is a string that's used as a label
 in a user interface. There are few user interface strings in the JSON
 response objects. Any links to Bing.com properties in the response objects
 apply the specified language.
 @param user_agent [String] The user agent originating the request. Bing uses
 the user agent to provide mobile users with an optimized experience. Although
 optional, you are encouraged to always specify this header. The user-agent
 should be the same string that any commonly used browser sends. For
 information about user agents, see [RFC
 2616](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html). The following
 are examples of user-agent strings. Windows Phone: Mozilla/5.0 (compatible;
 MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA;
 Lumia 822). Android: Mozilla / 5.0 (Linux; U; Android 2.3.5; en - us; SCH -
 I500 Build / GINGERBREAD) AppleWebKit / 533.1 (KHTML; like Gecko) Version /
 4.0 Mobile Safari / 533.1. iPhone: Mozilla / 5.0 (iPhone; CPU iPhone OS 6_1
 like Mac OS X) AppleWebKit / 536.26 (KHTML; like Gecko) Mobile / 10B142
 iPhone4; 1 BingWeb / 3.03.1428.20120423. PC: Mozilla / 5.0 (Windows NT 6.3;
 WOW64; Trident / 7.0; Touch; rv:11.0) like Gecko. iPad: Mozilla / 5.0 (iPad;
 CPU OS 7_0 like Mac OS X) AppleWebKit / 537.51.1 (KHTML, like Gecko) Version
 / 7.0 Mobile / 11A465 Safari / 9537.53
 @param client_id [String] Bing uses this header to provide users with
 consistent behavior across Bing API calls. Bing often flights new features
 and improvements, and it uses the client ID as a key for assigning traffic on
 different flights. If you do not use the same client ID for a user across
 multiple requests, then Bing may assign the user to multiple conflicting
 flights. Being assigned to multiple conflicting flights can lead to an
 inconsistent user experience. For example, if the second request has a
 different flight assignment than the first, the experience may be unexpected.
 Also, Bing can use the client ID to tailor web results to that client ID’s
 search history, providing a richer experience for the user. Bing also uses
 this header to help improve result rankings by analyzing the activity
 generated by a client ID. The relevance improvements help with better quality
 of results delivered by Bing APIs and in turn enables higher click-through
 rates for the API consumer. IMPORTANT: Although optional, you should consider
 this header required. Persisting the client ID across multiple requests for
 the same end user and device combination enables 1) the API consumer to
 receive a consistent user experience, and 2) higher click-through rates via
 better quality of results from the Bing APIs. Each user that uses your
 application on the device must have a unique, Bing generated client ID. If
 you do not include this header in the request, Bing generates an ID and
 returns it in the X-MSEdge-ClientID response header. The only time that you
 should NOT include this header in a request is the first time the user uses
 your app on that device. Use the client ID for each Bing API request that
 your app makes for this user on the device. Persist the client ID. To persist
 the ID in a browser app, use a persistent HTTP cookie to ensure the ID is
 used across all sessions. Do not use a session cookie. For other apps such as
 mobile apps, use the device's persistent storage to persist the ID. The next
 time the user uses your app on that device, get the client ID that you
 persisted. Bing responses may or may not include this header. If the response
 includes this header, capture the client ID and use it for all subsequent
 Bing requests for the user on that device. If you include the
 X-MSEdge-ClientID, you must not include cookies in the request.
 @param client_ip [String] The IPv4 or IPv6 address of the client device. The
 IP address is used to discover the user's location. Bing uses the location
 information to determine safe search behavior. Although optional, you are
 encouraged to always specify this header and the X-Search-Location header. Do
 not obfuscate the address (for example, by changing the last octet to 0).
 Obfuscating the address results in the location not being anywhere near the
 device's actual location, which may result in Bing serving erroneous results.
 @param location [String] A semicolon-delimited list of key/value pairs that
 describe the client's geographical location. Bing uses the location
 information to determine safe search behavior and to return relevant local
 content. Specify the key/value pair as <key>:<value>. The following are the
 keys that you use to specify the user's location. lat (required): The
 latitude of the client's location, in degrees. The latitude must be greater
 than or equal to -90.0 and less than or equal to +90.0. Negative values
 indicate southern latitudes and positive values indicate northern latitudes.
 long (required): The longitude of the client's location, in degrees. The
 longitude must be greater than or equal to -180.0 and less than or equal to
 +180.0. Negative values indicate western longitudes and positive values
 indicate eastern longitudes. re (required): The radius, in meters, which
 specifies the horizontal accuracy of the coordinates. Pass the value returned
 by the device's location service. Typical values might be 22m for GPS/Wi-Fi,
 380m for cell tower triangulation, and 18,000m for reverse IP lookup. ts
 (optional): The UTC UNIX timestamp of when the client was at the location.
 (The UNIX timestamp is the number of seconds since January 1, 1970.) head
 (optional): The client's relative heading or direction of travel. Specify the
 direction of travel as degrees from 0 through 360, counting clockwise
 relative to true north. Specify this key only if the sp key is nonzero. sp
 (optional): The horizontal velocity (speed), in meters per second, that the
 client device is traveling. alt (optional): The altitude of the client
 device, in meters. are (optional): The radius, in meters, that specifies the
 vertical accuracy of the coordinates. Specify this key only if you specify
 the alt key. Although many of the keys are optional, the more information
 that you provide, the more accurate the location results are. Although
 optional, you are encouraged to always specify the user's geographical
 location. Providing the location is especially important if the client's IP
 address does not accurately reflect the user's physical location (for
 example, if the client uses VPN). For optimal results, you should include
 this header and the X-MSEdge-ClientIP header, but at a minimum, you should
 include this header.
 @param aspect [ImageAspect] Filter images by the following aspect ratios.
 All: Do not filter by aspect.Specifying this value is the same as not
 specifying the aspect parameter. Square: Return images with standard aspect
 ratio. Wide: Return images with wide screen aspect ratio. Tall: Return images
 with tall aspect ratio. Possible values include: 'All', 'Square', 'Wide',
 'Tall'
 @param color [ImageColor] Filter images by the following color options.
 ColorOnly: Return color images. Monochrome: Return black and white images.
 Return images with one of the following dominant colors: Black, Blue, Brown,
 Gray, Green, Orange, Pink, Purple, Red, Teal, White, Yellow. Possible values
 include: 'ColorOnly', 'Monochrome', 'Black', 'Blue', 'Brown', 'Gray',
 'Green', 'Orange', 'Pink', 'Purple', 'Red', 'Teal', 'White', 'Yellow'
 @param country_code [String] A 2-character country code of the country where
 the results come from. For a list of possible values, see [Market
 Codes](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#market-codes).
 If you set this parameter, you must also specify the
 [Accept-Language](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#acceptlanguage)
 header. Bing uses the first supported language it finds from the languages
 list, and combine that language with the country code that you specify to
 determine the market to return results for. If the languages list does not
 include a supported language, Bing finds the closest language and market that
 supports the request, or it may use an aggregated or default market for the
 results instead of a specified one. You should use this query parameter and
 the Accept-Language query parameter only if you specify multiple languages;
 otherwise, you should use the mkt and setLang query parameters. This
 parameter and the
 [mkt](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#mkt)
 query parameter are mutually exclusive—do not specify both.
 @param count [Integer] The number of images to return in the response. The
 actual number delivered may be less than requested. The default is 35. The
 maximum value is 150. You use this parameter along with the offset parameter
 to page results.For example, if your user interface displays 20 images per
 page, set count to 20 and offset to 0 to get the first page of results.For
 each subsequent page, increment offset by 20 (for example, 0, 20, 40). Use
 this parameter only with the Image Search API.Do not specify this parameter
 when calling the Insights, Trending Images, or Web Search APIs.
 @param freshness [Freshness] Filter images by the following discovery
 options. Day: Return images discovered by Bing within the last 24 hours.
 Week: Return images discovered by Bing within the last 7 days. Month: Return
 images discovered by Bing within the last 30 days. Possible values include:
 'Day', 'Week', 'Month'
 @param height [Integer] Filter images that have the specified height, in
 pixels. You may use this filter with the size filter to return small images
 that have a height of 150 pixels.
 @param id [String] An ID that uniquely identifies an image. Use this
 parameter to ensure that the specified image is the first image in the list
 of images that Bing returns. The
 [Image](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#image)
 object's imageId field contains the ID that you set this parameter to.
 @param image_content [ImageContent] Filter images by the following content
 types. Face: Return images that show only a person's face. Portrait: Return
 images that show only a person's head and shoulders. Possible values include:
 'Face', 'Portrait'
 @param image_type [ImageType] Filter images by the following image types.
 AnimatedGif: Return only animated GIFs. Clipart: Return only clip art images.
 Line: Return only line drawings. Photo: Return only photographs(excluding
 line drawings, animated Gifs, and clip art). Shopping: Return only images
 that contain items where Bing knows of a merchant that is selling the items.
 This option is valid in the en - US market only.Transparent: Return only
 images with a transparent background. Possible values include: 'AnimatedGif',
 'Clipart', 'Line', 'Photo', 'Shopping', 'Transparent'
 @param license [ImageLicense] Filter images by the following license types.
 All: Do not filter by license type.Specifying this value is the same as not
 specifying the license parameter. Any: Return images that are under any
 license type. The response doesn't include images that do not specify a
 license or the license is unknown. Public: Return images where the creator
 has waived their exclusive rights, to the fullest extent allowed by law.
 Share: Return images that may be shared with others. Changing or editing the
 image might not be allowed. Also, modifying, sharing, and using the image for
 commercial purposes might not be allowed. Typically, this option returns the
 most images. ShareCommercially: Return images that may be shared with others
 for personal or commercial purposes. Changing or editing the image might not
 be allowed. Modify: Return images that may be modified, shared, and used.
 Changing or editing the image might not be allowed. Modifying, sharing, and
 using the image for commercial purposes might not be allowed.
 ModifyCommercially: Return images that may be modified, shared, and used for
 personal or commercial purposes. Typically, this option returns the fewest
 images. For more information about these license types, see [Filter Images By
 License Type](http://go.microsoft.com/fwlink/?LinkId=309768). Possible values
 include: 'All', 'Any', 'Public', 'Share', 'ShareCommercially', 'Modify',
 'ModifyCommercially'
 @param market [String] The market where the results come from. Typically, mkt
 is the country where the user is making the request from. However, it could
 be a different country if the user is not located in a country where Bing
 delivers results. The market must be in the form <language code>-<country
 code>. For example, en-US. The string is case insensitive. For a list of
 possible market values, see [Market
 Codes](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#market-codes).
 NOTE: If known, you are encouraged to always specify the market. Specifying
 the market helps Bing route the request and return an appropriate and optimal
 response. If you specify a market that is not listed in [Market
 Codes](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#market-codes),
 Bing uses a best fit market code based on an internal mapping that is subject
 to change. This parameter and the
 [cc](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#cc)
 query parameter are mutually exclusive—do not specify both.
 @param max_file_size [Integer] Filter images that are less than or equal to
 the specified file size. The maximum file size that you may specify is
 520,192 bytes. If you specify a larger value, the API uses 520,192. It is
 possible that the response may include images that are slightly larger than
 the specified maximum. You may specify this filter and minFileSize to filter
 images within a range of file sizes.
 @param max_height [Integer] Filter images that have a height that is less
 than or equal to the specified height. Specify the height in pixels. You may
 specify this filter and minHeight to filter images within a range of heights.
 This filter and the height filter are mutually exclusive.
 @param max_width [Integer] Filter images that have a width that is less than
 or equal to the specified width. Specify the width in pixels. You may specify
 this filter and maxWidth to filter images within a range of widths. This
 filter and the width filter are mutually exclusive.
 @param min_file_size [Integer] Filter images that are greater than or equal
 to the specified file size. The maximum file size that you may specify is
 520,192 bytes. If you specify a larger value, the API uses 520,192. It is
 possible that the response may include images that are slightly smaller than
 the specified minimum. You may specify this filter and maxFileSize to filter
 images within a range of file sizes.
 @param min_height [Integer] Filter images that have a height that is greater
 than or equal to the specified height. Specify the height in pixels. You may
 specify this filter and maxHeight to filter images within a range of heights.
 This filter and the height filter are mutually exclusive.
 @param min_width [Integer] Filter images that have a width that is greater
 than or equal to the specified width. Specify the width in pixels. You may
 specify this filter and maxWidth to filter images within a range of widths.
 This filter and the width filter are mutually exclusive.
 @param offset [Integer] The zero-based offset that indicates the number of
 images to skip before returning images. The default is 0. The offset should
 be less than
 ([totalEstimatedMatches](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#totalestimatedmatches)
 - count). Use this parameter along with the count parameter to page results.
 For example, if your user interface displays 20 images per page, set count to
 20 and offset to 0 to get the first page of results. For each subsequent
 page, increment offset by 20 (for example, 0, 20, 40). It is possible for
 multiple pages to include some overlap in results. To prevent duplicates, see
 [nextOffset](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#nextoffset).
 Use this parameter only with the Image API. Do not specify this parameter
 when calling the Trending Images API or the Web Search API.
 @param safe_search [SafeSearch] Filter images for adult content. The
 following are the possible filter values. Off: May return images with adult
 content. If the request is through the Image Search API, the response
 includes thumbnail images that are clear (non-fuzzy). However, if the request
 is through the Web Search API, the response includes thumbnail images that
 are pixelated (fuzzy). Moderate: If the request is through the Image Search
 API, the response doesn't include images with adult content. If the request
 is through the Web Search API, the response may include images with adult
 content (the thumbnail images are pixelated (fuzzy)). Strict: Do not return
 images with adult content. The default is Moderate. If the request comes from
 a market that Bing's adult policy requires that safeSearch is set to Strict,
 Bing ignores the safeSearch value and uses Strict. If you use the site: query
 operator, there is the chance that the response may contain adult content
 regardless of what the safeSearch query parameter is set to. Use site: only
 if you are aware of the content on the site and your scenario supports the
 possibility of adult content. Possible values include: 'Off', 'Moderate',
 'Strict'
 @param size [ImageSize] Filter images by the following sizes. All: Do not
 filter by size. Specifying this value is the same as not specifying the size
 parameter. Small: Return images that are less than 200x200 pixels. Medium:
 Return images that are greater than or equal to 200x200 pixels but less than
 500x500 pixels. Large: Return images that are 500x500 pixels or larger.
 Wallpaper: Return wallpaper images. You may use this parameter along with the
 height or width parameters. For example, you may use height and size to
 request small images that are 150 pixels tall. Possible values include:
 'All', 'Small', 'Medium', 'Large', 'Wallpaper'
 @param set_lang [String] The language to use for user interface strings.
 Specify the language using the ISO 639-1 2-letter language code. For example,
 the language code for English is EN. The default is EN (English). Although
 optional, you should always specify the language. Typically, you set setLang
 to the same language specified by mkt unless the user wants the user
 interface strings displayed in a different language. This parameter and the
 [Accept-Language](https://docs.microsoft.com/en-us/rest/api/cognitiveservices/bing-images-api-v7-reference#acceptlanguage)
 header are mutually exclusive; do not specify both. A user interface string
 is a string that's used as a label in a user interface. There are few user
 interface strings in the JSON response objects. Also, any links to Bing.com
 properties in the response objects apply the specified language.
 @param width [Integer] Filter images that have the specified width, in
 pixels. You may use this filter with the size filter to return small images
 that have a width of 150 pixels.
 @param [Hash{String => String}] A hash of custom headers that will be added
 to the HTTP request.

 @return [Concurrent::Promise] Promise object which holds the HTTP response.