-record(pool, {
    size :: integer(),
    queue_target :: integer(),
    queue_interval :: integer(),
    handle_open :: fun(() -> {ok, any()} | {error, db_pool:pool_error(any())}),
    handle_close :: fun((any()) -> {ok, nil} |
        {error, db_pool:pool_error(any())}),
    handle_idle :: fun((any()) -> nil),
    handle_active :: fun((any()) -> nil)
}).