Quote from docstring: "(link: ...) each tap must accept before the next item is distributed."
`
(def ch (chan))
(def m (mult ch))
(def t-1 (chan))
(def t-2 (chan))
(def t-3 (chan))
(def t-1-takes (atom []))
(defn log [l] (partial swap! l conj))
(tap m t-1)
(tap m t-2)
(tap m t-3)
(close! t-3)
(take! t-1 (log t-1-takes))
(take! t-1 (log t-1-takes)) ;; this take shouldn't be happening before
;; a take on t-2
(put! ch true)
(put! ch true)
@t-1-takes
;-> [true true] ;; but it does.
`
The reason is that the internal atom dctr is decreased twice when a tapped channel is already closed.
