static @NotNull Closeable startFlusher(@NotNull ScheduledExecutorService scheduler,
                                         @NotNull PersistentFSConnection connection,
                                         boolean gentleFlusher) {
    return gentleFlusher ?
           new GentleVFSFlusher(connection, scheduler) :
           new ClassicVFSFlusher(connection, scheduler);
  }
static @NotNull Closeable startFlusher(@NotNull ScheduledExecutorService scheduler,
                                         @NotNull PersistentFSConnection connection,
                                         boolean gentleFlusher)