+/* Search.
+ *
+ * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
+ * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
+ * all of the nodes in HMAP that would fall in the same bucket as HASH. STRUCT
+ * and MEMBER must be the name of the struct that contains the 'struct
+ * hmap_node' and the name of the 'struct hmap_node' member, respectively.
+ *
+ * These macros may be used interchangeably to search for a particular value in
+ * an hmap, see, e.g. shash_find() for an example. Usually, using
+ * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
+ * value is usually cheaper than comparing an entire hash map key. But for
+ * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
+ * it avoids doing two comparisons when a single simple comparison suffices.
+ *
+ * The loop should not change NODE to point to a different node or insert or
+ * delete nodes in HMAP (unless it "break"s out of the loop to terminate
+ * iteration).
+ *
+ * HASH is only evaluated once.
+ */