Pass special content to interceptors

[lorban]

Modify the AsyncContentProducer accordingly and update GzipHttpInputInterceptor to correctly handle the existing HttpInput.Content contract.

I have not modified the special contents (error and EOF) to make them return an empty buffer when getByteBuffer() is called as IMHO the Content contract already is clear on that: calling getByteBuffer() when isSpecial() returns true does throw ISE.

So IMHO if there is some code out there that calls Content.getByteBuffer() without first checking the special flag, it is in breach of the contract as it was documented since 10.0.0; the fact that we never passed special content to interceptors should be irrelevant.

[gregw]

Can we add and example to the javadoc somewhere like:

@Override
public HttpInput.Content readFrom(HttpInput.Content content) {
    if (content.hasContent())
        processContent(content.getByteBuffer());
    if (content.isEof())
        endProcessing();
    return processedContent();
}

[lorban]

@gregw I've added some javadoc to the Interceptor interface, including some code examples and a reference to GzipHttpInputInterceptor.

[sbordet]

Please fix redundant return.

[sbordet]

I see 3 variables here:

• what type of input content (some content, empty content, EOF content, error content)
• what the interceptor does with the input content (full consume, partial consume, no consume)
• what type of output content (null, empty, non-empty, EOF, error, throw)

I would like, if possible, to have tests that cover all combinations of the 3 variables above.
I'd be happy to see tests for the most common cases.
Otherwise I'm good.

[gregw]

Doh! forced push!!!!! I can't review just the changes since my last review!!!!