code: public CompletableFuture<CompletedCheckpoint> triggerSavepoint(
  			final long timestamp,
  			@Nullable final String targetLocation) {
  
  		final CheckpointProperties properties = CheckpointProperties.forSavepoint();
  		return triggerSavepointInternal(timestamp, properties, false, targetLocation);
  	}
docs: Triggers a savepoint with the given savepoint directory as a target.
  
  @param timestamp The timestamp for the savepoint.
  @param targetLocation Target location for the savepoint, optional. If null, the
  state backend's configured default will be used.
  @return A future to the completed checkpoint
  @throws IllegalStateException If no savepoint directory has been
  specified and no default savepoint directory has been
  configured