def create_transient_document(file_name, mime_type, file_handle)
      transient_document_response = Echochamber::Request.create_transient_document(token, file_name, file_handle, mime_type)
      transient_document_response.fetch("transientDocumentId")
    end
def create_transient_document(file_name, mime_type, file_handle)
      transient_document_response = Echochamber::Request.create_transient_document(token, file_name, file_handle, mime_type)
      transient_document_response.fetch("transientDocumentId")
    end
Creates a transient document for later referral

 @param file_name [String]
 @param mime_type [String]
 @param file_handle [File]
 @return [String] Transient document ID