Call onSubscribe on SingleObserver in RSocketRequester::fireAndForget (#694)
Call onSubscribe on SingleObserver in RSocketRequester::fireAndForget (#694)

Crashes internally
alexmalyshev/rsocket-cpp,phoad/rsocket-cpp,ReactiveSocket/reactivesocket-cpp,phoad/rsocket-cpp,ReactiveSocket/reactivesocket-cpp,ReactiveSocket/reactivesocket-cpp,phoad/rsocket-cpp,rsocket/rsocket-cpp,rsocket/rsocket-cpp,phoad/rsocket-cpp,rsocket/rsocket-cpp,alexmalyshev/rsocket-cpp,alexmalyshev/rsocket-cpp,phoad/rsocket-cpp,alexmalyshev/rsocket-cpp,rsocket/rsocket-cpp