introduce tcp client

lib/socketserver/GwTcpClient.h

@@ -0,0 +1,38 @@
+#pragma once
+#include "GwSocketConnection.h"
+class GwTcpClient
+{
+    static const unsigned long CON_TIMEOUT=10;
+    GwSocketConnection *connection = NULL;
+    IPAddress remoteAddress;
+    uint16_t port = 0;
+    unsigned long connectStart=0;
+    GwLog *logger;
+    int sourceId;
+    bool configured=false;
+
+public:
+    typedef enum
+    {
+        C_DISABLED = 0,
+        C_INITIALIZED = 1,
+        C_CONNECTING = 2,
+        C_CONNECTED = 3
+    } State;
+
+private:
+    State state = C_DISABLED;
+    void stop();
+    void startConnection();
+    void checkConnection();
+    bool hasConfig();
+
+public:
+    GwTcpClient(GwLog *logger);
+    ~GwTcpClient();
+    void begin(int sourceId,IPAddress address, uint16_t port,bool allowRead);
+    void loop(bool handleRead=true,bool handleWrite=true);
+    void sendToClients(const char *buf,int sourceId);
+    bool readMessages(GwMessageFetcher *writer);
+    bool isConnected();
+};