Subject: | Headers should be case-insensitive |
Headers are checked case-sensitively here https://metacpan.org/source/AVAR/Hijk-0.26/lib/Hijk.pm#L86 According to https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 "Field names are case-insensitive."
This code breaks in Elasticsearch 5.0 which now returns lowercase headers, and a request from Hijk just hangs until it times out.