code: public WebhookMessageBuilder setContent(String content)
      {
          Checks.check(content == null || content.length() <= 2000,
              "Content may not exceed 2000 characters!");
          if (content != null)
              this.content.replace(0, content.length(), content);
          else
              this.content.setLength(0);
          return this;
      }
docs: Sets the content of the resulting message.
  <br>This will override the previous content.
  
  @param  content
  The new content
  
  @throws java.lang.IllegalArgumentException
  If the provided content exceeds {@code 2000} characters in length
  
  @return The current WebhookMessageBuilder for chaining convenience