public Task BadGetGenericsAsync()
 {
     return(Assert.ThrowsExceptionAsync <NullReferenceException>(async() => {
         await foreach (var value in AsyncEnumerables.BadGetGenericsAsync <object>())
         {
         }
     }));
 }
 public Task BadGetReferencesAsyncWithoutAwait()
 {
     return(Assert.ThrowsExceptionAsync <NullReferenceException>(async() => {
         await foreach (var value in AsyncEnumerables.BadGetReferencesAsyncWithoutAwait())
         {
         }
     }));
 }
 public async Task GoodGetGenericsAsync()
 {
     await foreach (var value in AsyncEnumerables.GoodGetGenericsAsync <object>())
     {
     }
 }
 public async Task GoodGetReferencesAsyncWithoutAwait()
 {
     await foreach (var value in AsyncEnumerables.GoodGetReferencesAsyncWithoutAwait())
     {
     }
 }