feat: For application latencies timed stream a few cosmetic changes are needed (#1645)

## Description The comments in [this discussion](https://togithub.com/googleapis/nodejs-bigtable/pull/1639#pullrequestreview-3044883797) should be addressed in this PR. ## Impact Makes code cleaner. ## Testing This is just a follow-up on a PR.

Author: danieljbruce

src/timed-stream.ts

@@ -29,6 +29,11 @@ type TimedStreamOptions = TransformOptions & {
  ) => void;
 };
 
+/**
+ * StreamTimer is a utility class for measuring the elapsed time of stream
+ * operations. It provides methods to start and stop the timer, as well as
+ * retrieve the total duration in milliseconds.
+ */
 class StreamTimer {
  private startTime;
  private totalDuration;
@@ -62,7 +67,6 @@ export class TimedStream extends PassThrough {
  private readTimer = new StreamTimer();
  private transformTimer = new StreamTimer();
  constructor(options?: TimedStreamOptions) {
- // highWaterMark of 1 is needed to respond to each row
  super({
  ...options,
  objectMode: true,