Avoid data race when closing body

[DavyJohnes]

Some libraries which use http client call resp.Body.Close() multiple times from different goroutines, which leads to data race in tests because Close performa some mutations under the hood.
I understand this is mistake in those libraries, but real implementation in net/http doesn't produce data race is same condition. So I believe httmock should not as well.

[maxatome]

Hello, thanks for your contribution!
As you handle concurrent Close calls, couldn't we also protect Len and Read calls the same way? If the rationale is that users can do bad things, it makes sense, what do you think?
Just a detail, but could you move the mu field before body, as the mutex protects it, IMHO it is clearer.

[DavyJohnes]

Hello, thanks for your contribution! As you handle concurrent Close calls, couldn't we also protect Len and Read calls the same way? If the rationale is that users can do bad things, it makes sense, what do you think? Just a detail, but could you move the mu field before body, as the mutex protects it, IMHO it is clearer.

Sure! Done.

[maxatome]

Thanks!

[DavyJohnes]

@maxatome any ETA of next release with this fix?

[maxatome]

Done v1.4.1 just published.