code: @NotNull
      @ObjectiveCName("createChannelWithTitle:withAvatar:")
      public Promise<Integer> createChannel(String title, String avatarDescriptor) {
          return modules.getGroupsModule().createChannel(title, avatarDescriptor);
      }
docs: Create channel
  
  @param title            channel title
  @param avatarDescriptor descriptor of channel avatar (can be null if not set)
  @return Promise of channel id