Restore _pinfo.masked to a boolean state (0 or 1) to keep backward compatibility.

Author: mathieucarbou

src/AsyncWebSocket.cpp

@@ -541,17 +541,20 @@ void AsyncWebSocketClient::_onData(void *pbuf, size_t plen) {
 
     if (_pinfo.masked > 0 && _pinfo.masked < 5) {
       // Handle fragmented mask data - Safari may split the 4-byte mask across multiple packets
-      while (_pinfo.masked < 5) {
+      int mask_bytes_read = _pinfo.masked - 1;
+      while (mask_bytes_read < 4) {
         if (plen == 0) {
           // wait for more data
+          _pinfo.masked = mask_bytes_read + 1;
           _pstate = 1;
           return;
         }
-        _pinfo.mask[_pinfo.masked - 1] = data[0];
+        _pinfo.mask[mask_bytes_read] = data[0];
         data += 1;
         plen -= 1;
-        _pinfo.masked++;
+        mask_bytes_read++;
       }
+      _pinfo.masked = 1;  // restore boolean semantics: mask fully read
     }
 
     const size_t datalen = std::min((size_t)(_pinfo.len - _pinfo.index), plen);