public synchronized KeyedFuture<K, V> get(K key) {
		return get(key, function);
	}
Request the value for a given key

<p>
If this is called before any other get or put, the computation given at construction is
launched for the given key. A {@link CompletableFuture} is returned immediately. Subsequent
calls gets or puts on the same key return the same future without starting any new
computation.

@param key the key
@return a future, possible already completed, for the key's value
Ghidra/Framework/Generic/src/main/java/ghidra/async/AsyncLazyMap.java