Extension method to chain Tasks in the Promise Way Then-Catch

TaskExtensions.cs

using System;
using System.Threading.Tasks;

namespace Library.CustomExtensions
{
    public static class TaskExtensions
    {
      	public static async Task<TOut> Then<TIn, TOut>(
          this Task<TIn> task,
          Func<TIn, Task<TOut>> continuation,
          CancellationToken cancellationToken = default
        )
        {
            if (task == null)
            {
                throw new ArgumentNullException(nameof(task));
            }

            if (continuation == null)
            {
                throw new ArgumentNullException(nameof(continuation));
            }
		
            cancellationToken.ThrowIfCancellationRequested();
            TIn result = await task.ConfigureAwait(false);
            cancellationToken.ThrowIfCancellationRequested();
            return await continuation(result).ConfigureAwait(false);
        }
      
        public static async Task<T> Catch<T>(
          this Task<T> task, 
          Func<Exception, T> errorHandler, 
          CancellationToken cancellationToken = default
        )
        {
            if (task == null)
            {
                throw new ArgumentNullException(nameof(task));
            }

            if (errorHandler == null)
            {
                throw new ArgumentNullException(nameof(errorHandler));
            }
          
            cancellationToken.ThrowIfCancellationRequested();

            try
            {
                return await task.ConfigureAwait(false);
            }
            catch (Exception ex)
            {
                T result = errorHandler(ex);
                cancellationToken.ThrowIfCancellationRequested();
                return result;
            }
        }

        
    }
}