incorrectly demystifying used functions

[kirides]

System.Exception: OH NO: hello world
   at async Task demo.Program.Main()+(?) => { } in demo/Program.cs:line 22
   at async Task demo.Program.HandleOnSyncCtxAsync<T>(Action<T> handler, T state)+(?) => { } in demo/Program.cs:line 57
   at async Task demo.SynchronizationContextExtensions.PostAsync<T>(SynchronizationContext ctx, Action<T> d, T state)+(?) => { } in demo/Program.cs:line 101
   at async Task demo.SynchronizationContextExtensions.PostAsync<T>(SynchronizationContext ctx, Func<T, Task> d, T state) in demo/Program.rogram.cs:line 101cs:line 110                                                                                                                                                             cs:line 110
   at async Task demo.Program.HandleOnSyncCtxAsync<T>(Func<T, Task> handler, T state) in demo/Program.cs:line 55
   at async Task demo.Program.Main() in demo/Program.cs:line 20

i expected line 4 in the exception (at async Task demo.SynchronizationContextExtensions.PostAsync<T>(SynchronizationContext ctx, Action<T> d, T state)+(?) => { } in demo/Program.cs:line 101 )
to be the same method as line 5, as that is where the await happens. (the line number correctly indicates that)

Demo project:
demo.zip