Merge pull request #51 from jushutch/summarize-mistake-75

Write summary for mistake 75

docs/index.md

@@ -1726,6 +1726,29 @@ You should have a good reason to specify a channel size other than one for buffe
 
     Remain cautious with functions accepting a `time.Duration`. Even though passing an integer is allowed, strive to use the time API to prevent any possible confusion.
 
+Many common functions in the standard library accept a `time.Duration`, which is an alias for the `int64` type. However, one `time.Duration` unit represents one nanosecond, instead of one millisecond, as commonly seen in other programming languages. As a result, passing numeric types instead of using the `time.Duration` API can lead to unexpected behavior.
+
+A developer with experience in other languages might assume that the following code creates a new `time.Ticker` that delivers ticks every second, given the value `1000`:
+
+```go
+ticker := time.NewTicker(1000)
+for {
+	select {
+	case <-ticker.C:
+		// Do something
+	}
+}
+```
+
+However, because 1,000 `time.Duration` units = 1,000 nanoseconds, ticks are delivered every 1,000 nanoseconds = 1 microsecond, not every second as assumed.
+
+We should always use the `time.Duration` API to avoid confusion and unexpected behavior:
+```go
+ticker = time.NewTicker(time.Microsecond)
+// Or
+ticker = time.NewTicker(1000 * time.Nanosecond)
+```
+
  [Source code :simple-github:](https://github.com/teivah/100-go-mistakes/tree/master/src/10-standard-lib/75-wrong-time-duration/main.go)
 
 ### `time.After` and memory leaks (#76)