internal Mappings WithFailed(Mapping mapping)
{
var created = Created.Contains(mapping) ? Array.AsReadOnly(Created.Where(t => t != mapping).ToArray()) : Created;
var failed = !Failed.Contains(mapping) ? Array.AsReadOnly(Failed.Concat(new[] { mapping }).ToArray()) : Failed;
var pending = Pending.Contains(mapping) ? Array.AsReadOnly(Pending.Where(t => t != mapping).ToArray()) : Pending;
return(new Mappings(created, pending, failed));
}
