/// <summary>
/// Convert an output containing an array to an output containing its first element.
/// </summary>
/// <typeparam name="T">The type of elements in the array.</typeparam>
/// <param name="array">An array wrapped into <see cref="Output{T}"/>.</param>
/// <returns>An <see cref="Output{T}"/> containing the first array element.</returns>
public static Output <T> First <T>(this Output <ImmutableArray <T> > array) => array.GetAt(0);