:sig
bool memcache_set(u64 connection, String key, String value, u64 expires_in = 60*60)

:params
connection : connection handle
key : the entry's key
value : the value to be set
expires_in : optional expiration timeout, defaults to one hour
return value : true if the operation was successful

:see
>memcache

:content
Stores `value` under `key` on the Memcache server.

`expires_in` controls the expiration timeout and defaults to one hour.

:example
u64 conn = memcache_connect();
if(conn != 0) print(memcache_set(conn, "doc_set_key", "value") ? "stored" : "store failed", "\n");
else print("(requires a reachable memcached server)\n");
