In a configuration where the Readbuffer is set bigger than the actual Readsize and the Socket get highly stressed with messages, The Ringbuffer is crashing at Line 210. 

ASSERT: "pos >= 0 && pos <= size()" in file c:\users\qt\work\qt\qtbase\include\qtcore\5.11.2\qtcore\private\../../../../../src/corelib/tools/qringbuffer_p.h, line 210
Debug Error!

Program: C:\Qt\Qt5.11.2\5.11.2\msvc2015\bin\Qt5Cored.dll
Module: 5.11.2
File: c:\users\qt\work\qt\qtbase\include\qtcore\5.11.2\qtcore\private\../../../../../src/corelib/tools/qringbuffer_p.h
Line: 210