The prior method depended on IO:Socket:SSL to push the keep-alive options down to the socket but it only worked for recent versions of the module.
Instead, create the socket directly using IO::Socket::IP if available or IO:Socket:INET as a fallback. The keep-alive option is set directly on the socket before it is passed to IO:Socket:SSL.
Contributed by Marc Cousin.
Keepalives may help in situations where RST packets are being blocked by a firewall or otherwise do not arrive.
The C code uses select on all reads so it should never block, but add keepalives just in case.
Suggested by Ronan Dunklau.
File names with uncommon characters (e.g. @) caused authentication failures due to S3 encoding them correctly while the S3 driver did not.
Reported by Dan Farrell.
S3 (and gateways) always set content-length or transfer-encoding but HTTP 1.1 does not require it and proxies (e.g. HAProxy) may not include either.
Suggested by Adam K. Sumner.
The options accommodate systems where CAs are not automatically found by IO::Socket::SSL, i.e. RHEL7, or to load custom CAs.
Suggested by Scott Frazer.
