Dereference of potentially null field

If the field is actually null, then a null pointer dereference will occur. Field, which is statistically checked against null, is dereferenced.
/src/mongo/executor/network_interface_tl.cpp:1073: NULL_FIELD 175183 Reading field "_svcCtx", which is expected to possibly be "nullptr" in "this->this->cmdState->interface->_svcCtx" (checked 5 out of 6 times).