Several times now when reading, debugging and writing code I've wished that LWLockHeldByMe assertions specified the expected mode, especially where exclusive locking is required.
What do you think about something like the attached? See also an example of use. I will add this to the next commitfest.
I've wanted this before too, and was surprised it wasn't present. TBH I assumed there was a technical reason it wasn't and didn't investigate further because I just assumed it'd have been added with the original LWLockHeldByMe if it were simple.
