def post(salmon_url, envelope)
      http_client.headers(HTTP::Headers::CONTENT_TYPE => 'application/magic-envelope+xml').post(Addressable::URI.parse(salmon_url), body: envelope)
    end
def post(salmon_url, envelope)
      http_client.headers(HTTP::Headers::CONTENT_TYPE => 'application/magic-envelope+xml').post(Addressable::URI.parse(salmon_url), body: envelope)
    end
Deliver the magical envelope to a Salmon endpoint
 @param [String] salmon_url Salmon endpoint URL
 @param [String] envelope Magical envelope
 @raise [HTTP::Error] Error raised upon delivery failure
 @raise [OpenSSL::SSL::SSLError] Error raised upon SSL-related failure during delivery
 @return [HTTP::Response]