_appendText(text: string, style: DraftInlineStyle) {
    this.currentText += text;
    const characterMetadata = CharacterMetadata.create({
      style,
      entity: this.currentEntity,
    });
    this.characterList = this.characterList.push(
      ...Array(text.length).fill(characterMetadata),
    );
  }
Append a string of text to the internal buffer.