The address (host/port pair) of the pool
The id of the connection
The time it took to establish the connection.
In accordance with the definition of establishment of a connection
specified by ConnectionPoolOptions.maxConnecting,
it is the time elapsed between emitting a ConnectionCreatedEvent
and emitting this event as part of the same checking out.
Naturally, when establishing a connection is part of checking out,
this duration is not greater than
ConnectionCheckedOutEvent.duration.
A timestamp when the event was created
An event published when a connection is ready for use