code: func (builder *SSMLTextBuilder) AppendBreak(strength, time string) *SSMLTextBuilder {
  
  	if strength == "" {
  		// The default strength is medium
  		strength = "medium"
  	}
  
  	builder.buffer.WriteString(fmt.Sprintf("<break strength=\"%s\" time=\"%s\"/>", strength, time))
  
  	return builder
  }
docs: // AppendBreak will add a pause to the text to speech output. The default is a medium pause.
  // Refer to the SSML reference for the available strength values.