结果实现 IDisposable 时丢弃异步结果

Question

using var notNeeded = await foo();

foo returns 实现 IDisposable 的对象，但可以立即丢弃该对象。这行的惯用写法是什么？

using var notNeeded = await foo(); // (1) possible lint error: unused variable
using var _ = await foo(); // (2) looks clean but lives until the end of the function (which is rarely an issue)
using _ = await foo(); // (3) not legal
using (await foo()); // (4) possible lint error: possible mistaken empty statement
using (await foo()) {} // (5) looks like a mistake but actually does call Dispose() immediately

有没有更优雅的方式？

Answer 1

我会说立即处理它

var notNeeded = await foo();
notNedded.Dispose();

Answer 2

我倾向于立即处理 non-needed IDisposable 对象：

(await foo()).Dispose();

...如果是 IAsyncDisposable:

await (await foo()).DisposeAsync();

结果实现 IDisposable 时丢弃异步结果

Discard async result when result implements IDisposable

c#

async-await

idisposable