code: public ChangesetInfo comment(long id, String text)
  	{
  		if(text.isEmpty())
  		{
  			throw new IllegalArgumentException("Text must not be empty");
  		}
  
  		SingleElementHandler<ChangesetInfo> handler = new SingleElementHandler<>();
  
  		String apiCall = CHANGESET + "/" + id + "/comment?text=" + urlEncodeText(text);
  		osm.makeAuthenticatedRequest(apiCall, "POST", new ChangesetParser(handler));
  		return handler.get();
  	}
docs: Add a comment to the given changeset. The changeset must already be closed. Adding a comment
  to a changeset automatically subscribes the user to it.
  
  TODO monitor https://github.com/openstreetmap/openstreetmap-website/issues/1165
  
  @param id id of the changeset
  @param text text to add to the changeset. Must not be empty
  
  @return the updated changeset
  
  @throws OsmAuthorizationException if this application is not authorized to modify the map
  (Permission.MODIFY_MAP)
  @throws OsmConflictException if the changeset is not yet closed. (Only closed changesets can
  be commented