def request_headers(headers = {}, auth: true, gzip: true)
      headers = default_headers.merge(headers)
      headers.merge!(bearer_authorization_header) if auth
      headers[ACCEPT_ENCODING] = GZIP if gzip
      headers.reject{|_,v| v.nil? || (v.respond_to?(:empty?) && v.empty?)}
    end
def request_headers(headers = {}, auth: true, gzip: true)
      headers = default_headers.merge(headers)
      headers.merge!(bearer_authorization_header) if auth
      headers[ACCEPT_ENCODING] = GZIP if gzip
      headers.reject{|_,v| v.nil? || (v.respond_to?(:empty?) && v.empty?)}
    end
Build request headers. Removes empty headers.
 @example
   request_headers('Authorization' => nil)

 @param [Hash] headers
 @return [Hash]