docs: function splitField(chunk, strict) {
    const field = String(chunk);
    const index = field.indexOf(':');
  
    if (index === -1) {
      throw new SyntaxError(`field separator is not found: "${field}"`);
    }
  
    const label = field.slice(0, index);
    const value = field.slice(index + 1);
  
    if (strict && !(0, _validator.isValidLabel)(label)) {
      throw new SyntaxError(`unexpected character of label: "${label}"`);
    }
  
    if (strict && !(0, _validator.isValidValue)(value)) {
      throw new SyntaxError(`unexpected character of value: "${value}"`);
    }
  
    return {
      label,
      value
    };
  }