CA1842: Do not use 'WhenAll' with a single task

#Cause

System.Threading.Tasks.Task.WhenAll is called with a single task.

#Rule description

Using WhenAll with a single task may result in performance loss.

#How to fix violations

You should await or return the task instead.

#When to suppress warnings

Do not suppress a warning from this rule.

#See also

• CA1843: Do not use 'WaitAll' with a single task
• Performance rules