Simplify the cmd/http package overall by removing
custom plain text v/s tls connection detection, by
migrating to go1.12 and choose minimum version
to be go1.12
Also remove all the vendored deps, since they
are not useful anymore.
Without this PR minio server is writing an erroneous
response to clients on an idle connections which ends
up printing following message
```
Unsolicited response received on idle HTTP channel
```
This PR would avoid sending responses on idle connections
.i.e routine network errors.
An issue was reproduced when minio-js client functional
tests are setting lower case http headers, in our current
master branch we specifically look for canonical host header
which may be not necessarily true for all http clients.
This leads to a perpetual hang on the *net.Conn*.
This PR fixes regression caused by #6206 by handling the
case insensitivity.
This package provide customizable TCP net.Listener with various
performance-related options:
* SO_REUSEPORT. This option allows linear scaling server performance
on multi-CPU servers.
See https://www.nginx.com/blog/socket-sharding-nginx-release-1-9-1/ for details.
* TCP_DEFER_ACCEPT. This option expects the server reads from the accepted
connection before writing to them.
* TCP_FASTOPEN. See https://lwn.net/Articles/508865/ for details.