Do not use keep-alive or reuse them across requests

[Slind14]

Hi there,
the current implementation of curl is keeping connections open and not reusing them across requests. This is clocking up connections with TIME_WAIT:

netstat -tan | awk '$5 ~ /:813/ {print $6}' | sort | uniq -c | sort -n
      1 FIN_WAIT2
      2 ESTABLISHED
  92272 TIME_WAIT

I would suggest to avoid using keep-alive or switching to something like pecl-http which is using a shared pool of connections across requests according to this: https://stackoverflow.com/questions/41623271/php-and-persistent-http-connections/41643667#41643667

[isublimity]

I think, i disable keepAlive by default.

phpClickHouse/src/Transport/Http.php

Line 198 in b661da0

$new->connectTimeOut($this->_connectTimeOut)->keepAlive(); // one sec

phpClickHouse/src/Transport/CurlerRequest.php

Line 345 in 6a3e657

public function keepAlive($sec = 60)

[Slind14]

We migrated to pecl_http with custom post requests.

[isublimity]

build 1.3.2