docs: async def send_request(self, connection: Connection, payment_handle: int):
          """
          Approves the credential offer and submits a credential request. The result will be a credential stored in the prover's wallet.
          :param connection: connection to submit request from
          :param payment_handle: currently unused
          :return:
          Example:
          connection = await Connection.create(source_id)
          await connection.connect(phone_number)
          credential = await Credential.create(source_id, offer)
          await credential.send_request(connection, 0)
          """
          if not hasattr(Credential.send_request, "cb"):
              self.logger.debug("vcx_credential_send_request: Creating callback")
              Credential.send_request.cb = create_cb(CFUNCTYPE(None, c_uint32, c_uint32))
  
          c_credential_handle = c_uint32(self.handle)
          c_connection_handle = c_uint32(connection.handle)
          c_payment = c_uint32(payment_handle)
  
          await do_call('vcx_credential_send_request',
                        c_credential_handle,
                        c_connection_handle,
                        c_payment,
                        Credential.send_request.cb)