Class for asynchronous cached eager initialization of objects.

EagerLoad.cs

using System.Runtime.CompilerServices;

/// <summary>
/// EagerLoad<T> provides support for asynchronous cached eager initialization. This type is fully threadsafe.
/// Lazy<T> is for caching a value and synchronizing multiple threads attempting to get at that cached value.
/// Task<T> is for representing an asynchronous operation and making its result available in the future.
/// <see href="https://devblogs.microsoft.com/pfxteam/asynclazyt/"/>
/// <seealso href="https://blog.stephencleary.com/2012/08/asynchronous-lazy-initialization.html"/>
/// <seealso href="https://github.com/StephenCleary/AsyncEx/blob/master/src/Nito.AsyncEx.Coordination/AsyncLazy.cs"/>
/// </summary>
public sealed class EagerLoad
{
    /// <summary>
    /// The underlying lazy task.
    /// </summary>
    private readonly Lazy<Task> _instance;

    /// <summary>
    /// Initializes a new instance of the <see cref="AsyncLazy&lt;T&gt;"/> class.
    /// </summary>
    /// <param name="factory">The asynchronous delegate that is invoked on a background thread to produce the value when it is needed.</param>
    public EagerLoad(Func<Task> factory)
    {
        _instance = new Lazy<Task>(() => Task.Run(factory));
        _ = _instance.Value; // eager load
    }

    // Asynchronously await the initialized task.
    public async ValueTask Complete()
    {
        if (!_instance.IsCompleted)
            await _instance.Value.ConfigureAwait(false);
    }

    public ConfiguredTaskAwaitable ConfigureAwait(bool continueOnCapturedContext) => _instance.Value.ConfigureAwait(continueOnCapturedContext);

    /// <summary>
    /// Asynchronous infrastructure support. This method permits instances of <see cref="AsyncLazy&lt;T&gt;"/> to be awaited.
    /// </summary>
    //[EditorBrowsable(EditorBrowsableState.Never)]
    public TaskAwaiter GetAwaiter() => _instance.Value.GetAwaiter();
}