private static async Task <IEnumerable <T> > ToEnumerableAsync <T>([NotNull] Task <T> item)
where T : class
{
var result = await item.ConfigureAwait(false);
return(result == null ? null : MaterializationPolicyExtensions.ToEnumerable(result));
}
/// <summary>
/// Creates an <see cref="IAsyncEnumerable{T}"/> from a generator.
/// </summary>
/// <param name="policy">
/// The policy.
/// </param>
/// <param name="generateItem">
/// The generate Item.
/// </param>
/// <param name="dispose">
/// Function to call when disposing the generator.
/// </param>
/// <typeparam name="T">
/// The type of the items.
/// </typeparam>
/// <typeparam name="TState">
/// The type of the enumerator state.
/// </typeparam>
/// <returns>
/// The <see cref="IAsyncEnumerable{T}"/>.
/// </returns>
public static IAsyncEnumerable <T> CreateAsyncEnumerable <T, TState>(this IMaterializationPolicy policy, Func <TState, Task <T> > generateItem, [CanBeNull] Action <TState> dispose = null)
where TState : new()
where T : class
=> policy.CreateAsyncEnumerable(() => new GeneratorEnumerable <T, TState>(() => Task.FromResult(new TState()), context => MaterializationPolicyExtensions.ToEnumerableAsync(generateItem(context)), dispose));
/// <summary>
/// Creates an <see cref="IAsyncEnumerable{T}"/> from a generator.
/// </summary>
/// <param name="policy">
/// The policy.
/// </param>
/// <param name="initialize">
/// Initializes the enumerable, and returns the context.
/// </param>
/// <param name="generateItem">
/// Returns an item or <c>null</c> when no more items are available.
/// </param>
/// <param name="dispose">
/// Function to call when disposing the generator.
/// </param>
/// <typeparam name="T">
/// The type of the items.
/// </typeparam>
/// <typeparam name="TState">
/// The type of the enumerator state.
/// </typeparam>
/// <returns>
/// The <see cref="IAsyncEnumerable{T}"/>.
/// </returns>
public static IAsyncEnumerable <T> CreateAsyncEnumerable <T, TState>(this IMaterializationPolicy policy, Func <Task <TState> > initialize, Func <TState, Task <T> > generateItem, [CanBeNull] Action <TState> dispose = null)
where T : class
=> policy.CreateAsyncEnumerable(initialize, context => MaterializationPolicyExtensions.ToEnumerableAsync(generateItem(context)), dispose);
