Segfault / sentinel

[dirkx]

During a congested network - I got reproducable segaults in:

ESPAsyncWebServer/src/AsyncWebSocket.cpp

Line 646 in 67de9cd

const auto datalast = data[datalen];

it appears that data can be NULL (and datalen = 0). Given that in line

ESPAsyncWebServer/src/AsyncWebSocket.cpp

Line 698 in 67de9cd

if (datalen > 0)

this is only used when datalen >0 I suggest putting an

 uint8_t datalast;
 if (data && datalen>0)  datalast = data[datalen];

sentinel in.