PhoenixSocket.swift

public func sendMessage(with channelId: String,
                        event: String,
                        payload: Socket.Payload,
                        onSuccess: @escaping (Socket.Payload) -> (),
                        onError: @escaping (Socket.Payload) -> ()) {
  
  guard let socket = socket else { return }
  
  if socket.isConnected {
    socket.channels[channelId]?.send(event, payload: payload)?
      .receive("ok", callback: onSuccess)
      .receive("error", callback: onError)
  } else {
    // Call error callback when the socket is not connected
    onError([:])
    socket.connect()
  }    
}