Called after connect, once the connection has been registered with the pool.
Override this to attach error handlers or run post-connection setup queries.
Calling pool.destroy() on the connection from here does not throw, but it does not
close the connection either: the pool only takes ownership once this method resolves.
The connection returned by connect
Determine if a connection is still valid or not
Abstract Connection Manager
Connection manager which handles pooling & replication. Uses sequelize-pool for pooling
Param: connection