AsUnordered

在處理大量元素時,有序序列可能會損害效能。為了緩解這種情況,可以在不再需要序列順序時呼叫 AsUnordered

var sequence = Enumerable.Range(1, 10000).Select(x => -1 * x); // -1, -2, ...
var evenNumbers = sequence.AsParallel()
                          .OrderBy(x => x)
                          .Take(5000)
                          .AsUnordered()
                          .Where(x => x % 2 == 0) // This line won't be affected by ordering
                          .ToList();