Go のネストされた遅延関数で「recover()」が機能しないのはなぜですか?

package main

import "fmt"

func printRecover() {
    r := recover()
    fmt.Println("Recovered:", r)
}

func main() {
    defer printRecover()

    panic("OMG!")
}

Recovered: OMG!

package main

import "fmt"

func printRecover() {
    r := recover()
    fmt.Println("Recovered:", r)
}

func main() {
    defer func() {
        printRecover()
    }()

    panic("OMG!")
}

Recovered: <nil>
panic: OMG!

goroutine 1 [running]:
main.main()
    /tmp/sandbox898315096/main.go:15 +0x60

The return value of recover is nil if any of the following conditions holds:

- panic's argument was nil;
- the goroutine is not panicking;
- recover was not called directly by a deferred function.