This is a yielding function. When called, it will pause the Lua thread that called the function until a result is ready to be returned, without interrupting other scripts.
For thread safety, this property is not safe to read in an unsynchronized thread.
Retrieves the value of a key in the sorted map.
For a more in-depth look, take a look at the
articles/Memory Store|Memory Store article.
Key whose value to retrieve.
Key value, or nil – if there’s no item with the specified key.