add docs and examples

use lightws v0.6.5, change overlapping copy from ::copy_nonoverlappin…

…g to ::copy

exit immediately, do not handle accept failure(usually reaches fd lim…

…it), avoid falling into a infinite loop

Revert "set fd limit when starting"

use libkaminari v0.8.3, which allows custom tls alpn

remove targets without hard float

add brutal-shutdown feature notice

docs & examples

fix remote addr checker

set default connect timeout to 5s