Use ConfigureAwait in general-purpose library

[mjebrahimi]

If you’re writing general-purpose library code, use ConfigureAwait(false).
For more information you can read Stephen Cleary's article, ConfigureAwait FAQ

If you think ConfigureAwait(false) is no longer necessary in .NET Core or ASP.NET Core.
It's wrong.

ASP.NET Core has not own SynchronizationContext. That means that code running in an ASP.NET Core app by default won’t see a custom SynchronizationContext, which lessens the need for ConfigureAwait(false) running in such an environment.

But it doesn’t mean, however, that there will never be a custom SynchronizationContext or TaskScheduler present. If some user code (or other library code your app is using) sets a custom context and calls your code, or invokes your code in a Task scheduled to a custom TaskScheduler, then even in ASP.NET Core your awaits may see a non-default context or scheduler that would lead you to want to use ConfigureAwait(false).