During the switch of CirrusSearch to codfw elasticsearch cluster, we enabled connection pooling for all wikis. labswiki is running on Zend and as such does not have curl_init_pooled. The current code in PooledHttp seems robust, but experience show that search was broken on labswiki.

A fix was applied in configuration (https://gerrit.wikimedia.org/r/#/c/282145/) but making the class robust would be a better solution, if possible at all.