code: function executeSendData (client, ops, index, callback) {
    if (index >= ops.length) {
      callback();
      return;
    }
  
    sendMessage(client, ops[index], function () {
      executeSendData(client, ops, index+1, callback);
    });
  }
docs: Execute sending data starting at the specified index and
  using the provided client.
  
  @param {Socket} client - Socket to send data with
  @param {object} ops - Details of data to send
  @param {number} index - Starting index for sending
  @param {Function} callback - Function to call when done