fix crash for client connect async / fix #1912
fix crash for client connect async / fix #1912

StalderT/open62541,jpfr/open62541,jpfr/open62541,jpfr/open62541,open62541/open62541,JGrothoff/open62541,StalderT/open62541,JGrothoff/open62541,open62541/open62541,open62541/open62541,open62541/open62541,JGrothoff/open62541,jpfr/open62541,StalderT/open62541,JGrothoff/open62541,StalderT/open62541