Add streaming decoder support

[trumpetinc]

Adds support for streaming decode for Feign RequestLine methods that return InputStream or Reader.

To use:

  interface LargeStreamTestInterface {

    @RequestLine("GET /")
    InputStream getLargeStream();

    @RequestLine("GET /")
    Reader getLargeReader();
  }

public void test(){
  try(InputStream is = myLargeStreamTestInterface.getLargeStream()){
     // process the is
  }
}

Changes

1. InvocationContext now leaves the response stream open if the return type from the decoder implements Closeable
2. New InputStreamAndReaderDecoder class that can be registered with the Feign builder.decoder() method. Supports passing the decode request to a delegate if the method return type is not InputStream or Reader. If the return type is Reader, the charset of the response Content-Type header is used. If no charset is specified in the header, UTF-8 is assumed.
3. New ContentTypeParser utility method for obtaining information from the Content-Type header

[trumpetinc]

@yvasyliev I would appreciate code review/feedback if you have time!

[trumpetinc]

@velo can you please let me know what is going on with the failed security/snyk check? circleci says I don't have access...

[trumpetinc]

@velo making sure this didn't get lost in the shuffle. Can you please let me know what is going on with the failed security/snyk check? circleci says I don't have access... I would really like to get this SR in.

[yvasyliev]

I think this feature should be part of the DefaultDecoder

[velo]

what is going on with the failed security/snyk check?

🤦‍♂️

[trumpetinc]

@velo I didn't touch that file, and this PR has nothing to do with SOAP. So I don't understand why this PR would be held up for it...

What is the protocol for moving forward?

[trumpetinc]

I think this feature should be part of the DefaultDecoder

I am going to need some explanation for the API module vs the core module. Because to put it in DefaultDecoder, I need to put this new code into the API module.

I am puzzled about the fact that there is no explanation for why the classes in the API module were split out from core - and why there isn't a migration explanation for what appears to be a massive refactor.

Is there anything that explains what is going on with this API module?