/// <summary>
/// This extension method will enumerate this <see cref="IAsyncEnumerable{T}"/> into a <see cref="List{T}"/>.
/// </summary>
/// <typeparam name="T">The type of items.</typeparam>
/// <param name="enumerable">This <see cref="IAsyncEnumerable{T}"/>.</param>
/// <returns>A <see cref="List{T}"/> of enumerated items.</returns>
/// <exception cref="NullReferenceException">If this <see cref="IAsyncEnumerable{T}"/> is <c>null</c>.</exception>
public static async Task <List <T> > ToListAsync <T>(this IAsyncEnumerable <T> enumerable)
{
ArgumentValidator.ValidateNotNullReference(enumerable);
var retVal = new List <T>();
await enumerable.AddToCollectionAsync(retVal, (list, item) => list.Add(item));
return(retVal);
}
/// <summary>
/// This extension method will enumerate this <see cref="IAsyncEnumerable{T}"/> into a <see cref="IDictionary{TKey, TValue}"/>.
/// </summary>
/// <typeparam name="T">The type of items being enumerated.</typeparam>
/// <typeparam name="TKey">The type of dictionary keys.</typeparam>
/// <typeparam name="TValue">The type of dictionary values.</typeparam>
/// <param name="enumerable">This <see cref="IAsyncEnumerable{T}"/>.</param>
/// <param name="keySelector">The callback to potentially asynchronously create a dictionary key from enumerable item.</param>
/// <param name="valueSelector">The callback to potentially asynchronously create a dictionary value from enumerable item.</param>
/// <param name="equalityComparer">The optional <see cref="IEqualityComparer{T}"/> to use when creating dictionary.</param>
/// <returns>Asynchronously returns a <see cref="IDictionary{TKey, TValue}"/> containing keys and values as returned by <paramref name="keySelector"/> and <paramref name="valueSelector"/>.</returns>
/// <exception cref="NullReferenceException">If this <see cref="IAsyncEnumerable{T}"/> is <c>null</c>.</exception>
/// <exception cref="ArgumentNullException">If either of <paramref name="keySelector"/> or <paramref name="valueSelector"/> is <c>null</c>.</exception>
public static async Task <IDictionary <TKey, TValue> > ToDictionaryAsync <T, TKey, TValue>(
this IAsyncEnumerable <T> enumerable,
Func <T, ValueTask <TKey> > keySelector,
Func <T, ValueTask <TValue> > valueSelector,
IEqualityComparer <TKey> equalityComparer = null
)
{
ArgumentValidator.ValidateNotNullReference(enumerable);
ArgumentValidator.ValidateNotNull(nameof(keySelector), keySelector);
ArgumentValidator.ValidateNotNull(nameof(valueSelector), valueSelector);
var retVal = new Dictionary <TKey, TValue>(equalityComparer);
await enumerable.AddToCollectionAsync(retVal, async ( dictionary, item ) => dictionary.Add(await keySelector(item), await valueSelector(item)));
return(retVal);
}
