Race condition between write and flush in HttpClient.submit()

[NiteshKant]

HttpClient.submit() eventually results in a writeAndFlush() call on the ObservableConnection passing the HttpClientRequest (Code ref). Since, the content of the HttpClientRequest is written asynchronously (subscribing to the content Observable) it is possible that the flush (upon returning of write()) happens even before the entire content stream is written on the wire. This would result in unflushed content.