No HandshakeRequest in websocket subscription DataFetchingEnvironment

[alexdanielyan]

https://github.com/graphql-java/graphql-java-servlet/blob/e94d00e749dcc20a2ae474bb39072f3080800f06/src/main/java/graphql/servlet/internal/ApolloSubscriptionProtocolHandler.java#L60-L62

I found out that there is no HandshakeRequest in websocket subscription DataFetchingEnvironment GraphqlContext.
Why there is no (HandshakeRequest) session.getUserProperties().get(HANDSHAKE_REQUEST_KEY) builder argument that should be passed in GraphqlContext constructor?