release method
Implementation
void release(DatabaseDriver driver) {
if (_inUse.remove(driver)) {
// If there are waiting requests, give them the connection
if (_waitingQueue.isNotEmpty) {
final completer = _waitingQueue.removeFirst();
_inUse.add(driver);
completer.complete(driver);
} else {
// No waiting requests, return to available pool
_available.add(driver);
}
}
}