Provided PipedInputStream should not be closed

[pdudits]

As reported in #2497 and #1896 utilizing readingOut and readingErr to capture execution output looses last chunk of data.

This is caused by ExecWebSocketListener closing both provided PipedInputStream as well as producing PipedOutputStream.

When PipedOutputStream is closed, it only notifies connected PipedInputStream that no more data will be transferred.
PipedInputStream would still make the rest of its buffer available.

However as soon as close is invoked on PipedInputStream its buffer pointer is reset and any further attempt to read will cause an IOException("Pipe closed").

This causes data loss and exceptions thrown to client, and the workaround is to suppress call to close():

            PipedInputStream out = new PipedInputStream() {
                @Override
                public void close() throws IOException {
                    // k8s client errornously closes the stream when execution finishes.
                    // this prevents reading the rest of the buffer
                }
            };
            client.pods().withName(pod.getMetadata().getName())
                    .inContainer(container.getName())
                    .readingOutput(out)
                    .exec(command);

[rohanKanojia]

@pdudits : Thanks for reporting this, Would it be possible for you to contribute a fix for this issue?

[rohanKanojia]

@shawkins : Do you think we can take care of this issue in #3169 ?

[pdudits]

I can try, should be ok as long as I don't hit major obstacles in building (for example, master doesn't seem to compile on 1.8.0_292 at first attempt).

Also in ExecWebSocketListener#inputStreamOrPipe a connect call seems to be missing that would connect the provided PipeOutputStream to input. (edit: I misread the code)