use nonblocking write for serial

lib/serial/GwSerial.h

@@ -0,0 +1,24 @@
+#ifndef _GWSERIAL_H
+#define _GWSERIAL_H
+#include "driver/uart.h"
+#include "GwLog.h"
+#include "GwBuffer.h"
+class SerialWriter;
+class GwSerial{
+    private:
+        GwBuffer *buffer;
+        GwLog *logger; 
+        SerialWriter *writer;
+        uart_port_t num;
+        bool initialized=false;
+    public:
+        static const int bufferSize=200;
+        GwSerial(GwLog *logger,uart_port_t num);
+        ~GwSerial();
+        int setup(int baud,int rxpin,int txpin);
+        bool isInitialized();
+        size_t enqueue(const uint8_t *data, size_t len);
+        GwBuffer::WriteStatus write();
+        const char *read();
+};
+#endif