private void runCallback(Path path) {
        fileSystemWatchContext.watchEvents().stream().filter(
                ctx -> path.startsWith(ctx.dirPath())).forEach(ctx -> {
            try {
                ctx.runCallback();
            } catch (Exception e) {
                logger.warn("Unexpected error from listener: {} ", path, e);
            }
        });
    }
Initializes a runnable which watches files.
@param watchService the {@code WatchService} to receive events from
@param fileSystemWatchContext the context which contains target files
core/src/main/java/com/linecorp/armeria/client/endpoint/FileWatcherRunnable.java