resource sync
  type item = int
  op get() returns item {call}
  op put(item) {call}
body sync()
  op try(cap(item))
  process manager {
    cap(item) go
    item x;
    while(true) {
#      in put(x) -> receive try(go); send go(x); ni
       receive put(x); receive try(go); send go(x);
    }
  }
  proc get() returns x {
    op take(item)
    send try(take)
    receive take(x)
  }
end sync