Bugfix for stuck in write method of WiFiClient and WiFiClientSecure until the remote peer closed connection (#6104)

* Bugfix - write method of WiFiClient and WiFiClientSecure can stuck forever

* Adjustment of uint8_t to bool to have it clear flag

Author: sislakd

libraries/ESP8266WiFi/src/include/ClientContext.h

@@ -437,7 +437,7 @@ class ClientContext
     size_t _write_from_source(DataSource* ds)
     {
         assert(_datasource == nullptr);
-        assert(_send_waiting == 0);
+        assert(!_send_waiting);
         _datasource = ds;
         _written = 0;
         _op_start_time = millis();
@@ -455,10 +455,10 @@ class ClientContext
                 break;
             }
 
-            ++_send_waiting;
+            _send_waiting = true;
             esp_yield();
         } while(true);
-        _send_waiting = 0;
+        _send_waiting = false;
 
         if (_sync)
             wait_until_sent();
@@ -525,8 +525,8 @@ class ClientContext
 
     void _write_some_from_cb()
     {
-        if (_send_waiting == 1) {
-            _send_waiting--;
+        if (_send_waiting) {
+            _send_waiting = false;
             esp_schedule();
         }
     }
@@ -650,7 +650,7 @@ class ClientContext
     size_t _written = 0;
     uint32_t _timeout_ms = 5000;
     uint32_t _op_start_time = 0;
-    uint8_t _send_waiting = 0;
+    bool _send_waiting = false;
     uint8_t _connect_pending = 0;
 
     int8_t _refcnt;