Add events: Mutating(Add) -> Adding(1,2,3) -> Mutated(Add) -> Added(1,2,3)
Filtered to writes: 1 write event, 0 read events, 2 items
Synchronized list: 1000 concurrent adds kept, 1000 read-then-add pairs in order
Stacked decorators: 500 synchronized adds raised 500 events
Projected view wrote 42 into the underlying list
