@Override
    public void close() throws IOException {
        // Complete the initialLoadFuture, if it hasn't been completed already.
        initialLoadFuture.completeExceptionally(new TimeoutException("The authorizer was " +
            "closed before the initial load could complete."));
    }
The current data. We use a read-write lock to synchronize reads and writes to the data. We
expect one writer and multiple readers accessing the ACL data, and we use the lock to make
sure we have consistent reads when writer tries to change the data.
metadata/src/main/java/org/apache/kafka/metadata/authorizer/StandardAuthorizer.java