lean into examples

examples/timers/timers.go

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+// We often want to execute Go code at some point in the
+// future, or repeatedly at some interval. Go's built-in
+// timer and ticker features make both of these tasks
+// easy. We'll look first at timers and then
+// at [tickers](tickers).
+
+package main
+
+import "time"
+import "fmt"
+
+func main() {
+
+    // Timers represent a single event in the future. You
+    // tell the timer how long you want to wait, and it
+    // provides a channel that will be notified at that
+    // time. This timer will wait 2 seconds.
+    timer1 := time.NewTimer(time.Second * 2)
+
+    // The `<-timer1.C` blocks on the timer's channel `C`
+    // until it sends a value indicating that the timer
+    // expired.
+    <-timer1.C
+    fmt.Println("Timer 1 expired")
+
+    // If you just wanted to wait, you could have used
+    // `time.Sleep`. One reason a timer may be useful is
+    // that you can cancel the timer before it expires.
+    // Here's an example of that.
+    timer2 := time.NewTimer(time.Second)
+    go func() {
+        <-timer2.C
+        fmt.Println("Timer 2 expired")
+    }()
+    stop2 := timer2.Stop()
+    if stop2 {
+        fmt.Println("Timer 2 stopped")
+    }
+}

examples/timers/timers.sh

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+// The first timer will expire ~2s after we start the
+// program, but the second should be stopped before it has
+// a chance to expire.
+$ go run timers.go
+Timer 1 expired
+Timer 2 stopped