apply filters and loggers at host and path level, when file.custom-handler at global level is applied

if we add a fd mapping with src and dest being the same, dup2 becomes a no-op and the fd gets closed; avoid that

[http3] add end-to-end test for prioritization

Hide h2olog endpoint unless accessed via UNIX socket, update docs

[h2olog] h2olog v2 part 1 (core)

fix h3 CI issues with t/50mruby-middleware.t

fix h3 CI issues with t/50mruby-http-request.t

[http3] send server-timing header

remove content-length response header as we rewrite; otherwise the entire response might not reach the client as curl-ngtcp2 might swallow what has been received due to the presence of immediate reset

the esi handler has been emitting c-l longer than the size of actual body being synthesized - this has led to an early close that has been converted (properly) to an error; and that can lead to total data loss in h3; see other commit

when the H3 server closes the stream short of sending as much as that declared in `content-length`, curl-ngtcp2 might not surface the partially delivered bytes; add wait to force it dto do so

[http3] send server-timing headers, but not trailers for the time being as it is going to be complex

enable h3 tests using run_with_curl

add parens to suppress warning

Expect: 100-continue

SKIP_PROG_EXISTS is essentially a feature requirement, it is only turned on on ubuntu2204 so we can reuse it