add flush() to unref() see #50

Author: Links2004

cores/esp8266/WString.h

@@ -33,6 +33,7 @@
 class StringSumHelper;
 
 typedef char* __FlashStringHelper;
+//#define F(str)  []() -> const char * { static const char tmp[] ICACHE_RODATA_ATTR = str; return &tmp[0]; }()
 #define F(str) str
 
 // The string class

libraries/ESP8266WiFi/src/include/ClientContext.h

@@ -77,6 +77,7 @@ class ClientContext
         DEBUGV(":ur %d\r\n", _refcnt);
         if (--_refcnt == 0)
         {
+            flush();
             if (_pcb)
             {
                 tcp_arg(_pcb, NULL);