code: @CheckReturnValue
      public ChannelAction setUserlimit(Integer userlimit)
      {
          if (type != ChannelType.VOICE)
              throw new UnsupportedOperationException("Can only set the userlimit for a VoiceChannel!");
          if (userlimit != null && (userlimit < 0 || userlimit > 99))
              throw new IllegalArgumentException("Userlimit must be between 0-99!");
          this.userlimit = userlimit;
          return this;
      }
docs: Sets the userlimit for the new VoiceChannel
  
  @param  userlimit
  The userlimit for the new VoiceChannel or {@code null}/{@code 0} to use no limit,
  
  @throws UnsupportedOperationException
  If this ChannelAction is not for a VoiceChannel
  @throws IllegalArgumentException
  If the provided userlimit is negative or above {@code 99}
  
  @return The current ChannelAction, for chaining convenience