You're seeing just the callback checkin, go back to DBConnection module for more information.


checkin(state :: any()) ::
  {:ok, new_state :: any()} | {:disconnect, Exception.t(), new_state :: any()}

Checks in the state to the connection process. Return {:ok, state} to allow the checkin or {:disconnect, exception, state} to disconnect.

This callback is called when the control of the state is passed back to the connection process. It should reverse any changes to the connection state made in checkout/1.

This callback is called in the connection process.