allowRelease method

void allowRelease(FutureOr<void> onRelease())

Tells the parent Pool that the resource associated with this resource is no longer necessary, but should remain allocated until more resources are needed.

When Pool.request is called and there are no remaining available resources, the onRelease callback is called. It should free the resource, and it may return a Future or null. Once that completes, the Pool.request call will complete to a new PoolResource.

This is useful when a resource's main function is complete, but it may produce additional information later on. For example, an isolate's task may be complete, but it could still emit asynchronous errors.

Any errors thrown by onRelease or the future it returns are ignored.

Implementation

void allowRelease(FutureOr<void> Function() onRelease) {
  if (_released) {
    throw StateError('A PoolResource may only be released once.');
  }
  _released = true;
  _pool._onResourceReleaseAllowed(onRelease);
}