Clojure partition-at

While working with some code, I noticed what appears to be a missing function. I wanted to use something like partition-by, which splits the collection each time the passed function returns a new value. Except I wanted it to split whenever the passed function returns true, instead of when the return value changes. Anyways, here it is:

(defn partition-at
  "Like partition-by but will start a new run when f returns true"
  [f coll]
  (lazy-seq
   (when-let [s (seq coll)]
     (let [run (cons (first s) (take-while #(not (f %)) (rest s)))]
       (cons run (partition-at f (drop (count run) s)))))))