In this method we can put the logic needed to prepare the connection
right before sending the queued commands to the server (e.g. switching
to the master server when connected in replication mode).
First of all we completely removed the concept of pipeline executors.
Now pipelines can be easily customized by extending our default class
Predis\Pipeline\Pipeline.
Tests coverage for the Predis\Pipeline namespace is decent but can be
definitely improved while test cases can be beautified.
Daniele Alessandri