render method Null safety

String render(
  1. [StringBuffer? buffer]
)

Implementation

String render([StringBuffer? buffer]) {
  buffer ??= StringBuffer();
  buffer.write(value);
  renderField('charset', charset, true, buffer);
  renderField('boundary', boundary, true, buffer);
  if (isFlowedFormat == true) {
    renderField('format', 'flowed', false, buffer);
  }
  renderRemainingFields(buffer, exclude: ['charset', 'boundary', 'format']);
  return buffer.toString();
}