Closes a channel pool.
You should not call this function directly because the channel pool is already registered on a connection which actually will also try to remove the pool registered when the connection is destroyed. So, you can actually leave this function and let the connection destroying process to do the job.
This function will remove the channel pool from the hash the connection have that will activate this function which finally close all channels and deallocated all resources.
You may wondering why channel pool destroying is threat this way. This is because a channel pool doesn't exists without the connection concept which means the connection have hard references to channels pools created and must be notified when some pool is not going to be available.
This function may block you because a vortex_channel_close will be issued over all channels.
This function is also used as a destroy function because it frees all resources allocated by the pool after closing all channels pool.