code: func yaml_emitter_check_simple_key(emitter *yaml_emitter_t) bool {
  	length := 0
  	switch emitter.events[emitter.events_head].typ {
  	case yaml_ALIAS_EVENT:
  		length += len(emitter.anchor_data.anchor)
  	case yaml_SCALAR_EVENT:
  		if emitter.scalar_data.multiline {
  			return false
  		}
  		length += len(emitter.anchor_data.anchor) +
  			len(emitter.tag_data.handle) +
  			len(emitter.tag_data.suffix) +
  			len(emitter.scalar_data.value)
  	case yaml_SEQUENCE_START_EVENT:
  		if !yaml_emitter_check_empty_sequence(emitter) {
  			return false
  		}
  		length += len(emitter.anchor_data.anchor) +
  			len(emitter.tag_data.handle) +
  			len(emitter.tag_data.suffix)
  	case yaml_MAPPING_START_EVENT:
  		if !yaml_emitter_check_empty_mapping(emitter) {
  			return false
  		}
  		length += len(emitter.anchor_data.anchor) +
  			len(emitter.tag_data.handle) +
  			len(emitter.tag_data.suffix)
  	default:
  		return false
  	}
  	return length <= 128
  }
docs: // Check if the next node can be expressed as a simple key.