/// <inheritdoc />
 public override string ToString()
 {
     return($"Promise<{TypeNameOfAsync?.ToString() ?? "void"}>");
 }
 /// <summary>Serves as the default hash function.</summary>
 /// <returns>A hash code for the current object.</returns>
 public override int GetHashCode()
 {
     return(TypeNameOfAsync != null ? TypeNameOfAsync.GetHashCode() : 0);
 }