Related: #3122
Motivation:
The HttpStaticFileServer example writes the LastHttpContent twice at the
end of the transfer. HttpChunkedInput already produces a
LastHttpContent at the end of the stream, so there's no reason to write
another.
Modifications:
Do not write LastHttpContent in HttpStaticFileServerHandler when
HttpChunkedInput is used to transfer a file.
Result:
HttpStaticFileServer does not violates the protocol anymore.
b9f575352b