/// <summary>
/// Convenience method to asynchronously get <see cref="AsyncResourceUsage{TResource}"/> from this <see cref="AsyncResourcePool{TResource}"/> by first calling <see cref="AsyncResourcePool{TResource}.GetResourceUsage"/> and then <see cref="AsyncResourceUsage{TResource}.AwaitForResource"/>.
/// </summary>
/// <typeparam name="TResource">The type of resources handled by this pool.</typeparam>
/// <param name="pool">This <see cref="AsyncResourcePool{TResource}"/>.</param>
/// <param name="token">The <see cref="CancellationToken"/> to bind returned <see cref="AsyncResourceUsage{TResource}"/> to.</param>
/// <returns>Asynchronously returns <see cref="AsyncResourceUsage{TResource}"/> which has its <see cref="AsyncResourceUsage{TResource}.Resource"/> property ready to use without further awaiting.</returns>
/// <exception cref="NullReferenceException">If this <see cref="AsyncResourcePool{TResource}"/> is <c>null</c>.</exception>
public static async Task <AsyncResourceUsage <TResource> > GetResourceUsageAsync <TResource>(this AsyncResourcePool <TResource> pool, CancellationToken token)
{
var retVal = pool.GetResourceUsage(token);
await retVal.AwaitForResource();
return(retVal);
}
/// <summary>
/// Takes an existing resource or creates a new one, runs the given asynchronous callback for it, and returns it back into the pool.
/// </summary>
/// <param name="pool">This <see cref="AsyncResourcePool{TResource}"/>.</param>
/// <param name="user">The asynchronous callback to use the resource.</param>
/// <param name="token">The optional <see cref="CancellationToken"/> to use during asynchronous operations inside <paramref name="user"/> callback.</param>
/// <returns>A task which completes when <paramref name="user"/> callback completes and resource is returned back to the pool.</returns>
/// <exception cref="NullReferenceException">If this <see cref="AsyncResourcePool{TResource}"/> is <c>null</c>.</exception>
public static async Task UseResourceAsync <TResource>(this AsyncResourcePool <TResource> pool, Func <TResource, Task> user, CancellationToken token)
{
var usage = pool.GetResourceUsage(token);
try
{
await usage.AwaitForResource();
await user(usage.Resource);
}
finally
{
await usage.DisposeAsync();
}
}
