Disallow reading from a closed ResponseStream

[omus]

Closing a ResponseStream would still allow you to continue reading content from the buffer. I've updated the code to work similarly to how IOStream's behave.

[codecov-io]

Codecov Report

Merging #144 into master will decrease coverage by 0.74%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #144      +/-   ##
==========================================
- Coverage   70.17%   69.42%   -0.75%     
==========================================
  Files           4        4              
  Lines         523      520       -3     
==========================================
- Hits          367      361       -6     
- Misses        156      159       +3

Impacted Files	Coverage Δ
src/streaming.jl	74.59% <100%> (-4.41%)	⬇️
src/Requests.jl	60% <0%> (-1.23%)	⬇️
src/multipart.jl	61.73% <0%> (+2.6%)	⬆️

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[aviks]

@omus should we merge this?

[omus]

@aviks I'm not sure that this should be the behaviour anymore based upon JuliaWeb/HTTP.jl#45 (comment). @samoconnor can you elaborate on why you want to be able to read from the buffer when the socket has been closed?

[samoconnor]

Hi @aviks, perhaps there is confusion about the reader closing the stream vs the server closing the stream.

If the server has closed the stream (or the connection was unexpectedly lost), the reader should be able to continue to read whatever was received from the buffer until there is nothing left to read.

If the reader calls close on the stream, that indicates that they do not intend to read anything else from the stream, I think any subsequent calls to read or eof for that stream should result in an exception e.g. "ERROR: Attempted access to closed stream".

Of course, if this assumes a uni-directional stream. If the stream is read/write, then there needs to be a way to close the write half without closing the read half (i.e. shutdown(socket, SHUT_WR)) so that the writer can signal that they have finished sending a request, but can still receive a response from the read half of the stream.