@VisibleForTesting
    CompletableFuture<Void> getReadaheadInflightReadaheadCf() {
        return readahead.inflightReadaheadCf;
    }
This method is only for unit testing.
inflightReadaheadCf is empty, the task has been completed
inflightReadaheadCf is not empty, the task may be completed

@return readahead.inflightReadaheadCf
s3stream/src/main/java/com/automq/stream/s3/cache/blockcache/StreamReader.java