Why not setkeepalive on tcp socket ?

[NicoAdrian]

For each healthcheck, you seem to close the socket, why not put it into the connection pool with sock:setkeepalive() instead ?

lua-resty-upstream-healthcheck/lib/resty/upstream/healthcheck.lua

Line 275 in 346f3a6

sock:close()

[zhuizhuhaomeng]

the healthcheck.lua does not parse the full http response, maybe there are some data left in the socket. So we can not put it into the pool