code: public BoxRequestsFile.AddTaggedCommentToFile getAddTaggedCommentRequest(String fileId, String taggedMessage) {
          BoxRequestsFile.AddTaggedCommentToFile request = new BoxRequestsFile.AddTaggedCommentToFile(
                  fileId, taggedMessage, getCommentUrl(), mSession);
          return request;
      }
docs: Gets a request for adding a comment with tags that mention users.
  The server will notify mentioned users of the comment.
  
  Tagged users must be collaborators of the parent folder.
  Format for adding a tag @[userid:username], E.g. "Hello @[12345:Jane Doe]" will create a comment
  'Hello Jane Doe', and notify Jane that she has been mentioned.
  
  @param fileId    id of the file to add the comment to
  @param taggedMessage   message for the comment that will be added
  @return  request to add a comment to a file