+upon success and NULL will be returned on failure. MEMCACHD_END is returned
+by the *error value when all objects that have been found are returned.
+The final value upon MEMCACHED_END is null. Values returned by
+memcached_fetch() musted be free'ed by the caller.
+
+memcached_fetch_result() is used to return a memcached_result_st(3) structure
+from a memcached server. The result object is forward compatible with changes
+to the server. For more information please refer to the memcached_result_st(3)
+help. This function will dynamically allocate a result structure for you
+if you do not pass one to the function.
+
+memcached_fetch_execute() is a callback function for result sets. Instead
+of returning the results to you for processing, it passes each of the
+result sets to the list of functions you provide. It passes to the function
+a memcached_st that can be cloned for use in the called function (it can not
+be used directly). It also passes a result set which does not need to be freed.
+Finally it passes a "context". This is just a pointer to a memory reference
+you supply the calling function. Currently only one value is being passed
+to each function call. In the future there will be an option to allow this
+to be an array.
+
+memcached_get_by_key() and memcached_mget_by_key() behave in a similar nature
+as memcached_get() and memcached_mget(). The difference is that they take
+a master key that is used for determining which server an object was stored
+if key partitioning was used for storage.