Motivation:
`addHttp2ToHttpHeaders(int streamId, Http2Headers sourceHeaders, FullHttpMessage destinationMessage, boolean addToTrailer)`
should match
`addHttp2ToHttpHeaders(int streamId, Http2Headers inputHeaders, HttpHeaders outputHeaders, HttpVersion httpVersion, boolean isTrailer, boolean isRequest)`.
However, the `Http2Headers` variable name is different.
Modification:
Changed `sourceHeaders` to `inputHeaders`.
Result:
Variable and JavaDoc naming now correct.