Handling close connection with GraphQLWSHandler #450

Job	Run time
IT / GraphQLWS-Tests (18.13.0)	19m 5s
IT / SockJS-WriteHandler-Tests (16.13.1)	13m 32s
CI (windows-latest, 11) / Run tests	8m 58s
CI (ubuntu-latest, 17) / Run tests	6m 54s
CI (ubuntu-latest, 11) / Run tests	7m 31s
Deploy / Deploy to OSSRH	2m 27s
	58m 27s

Provide feedback