code: public int createConversation(String subject, String text,
  			List<Integer> participants) {
  		return createConversation(subject, text, participants, null);
  	}
docs: Creates a new conversation with a list of users. Once a conversation is
  started, the participants cannot (yet) be changed.
  
  @param subject
  The subject of the conversation
  @param text
  The text of the first message in the conversation
  @param participants
  List of participants in the conversation (not including the
  sender)
  @return The id of the newly created conversation