using<T>  method 
      
T
using<T>( 
    
- T resource,
 - void releaseCallback(
- T
 
 
Registers resource in this arena.
Executes releaseCallback on releaseAll.
Returns resource again, to allow for easily inserting
arena.using(resource, ...) where the resource is allocated.
Implementation
T using<T>(T resource, void Function(T) releaseCallback) {
  _ensureInUse();
  releaseCallback = Zone.current.bindUnaryCallback(releaseCallback);
  _managedResourceReleaseCallbacks.add(() => releaseCallback(resource));
  return resource;
}