to define an interface called <code>Locker</code>:
</p>

<pre>
type Locker interface {
	Lock()
	Unlock()
}
</pre>

<p>
If <code>S1</code> and <code>S2</code> also implement
</p>

<pre>
func (p T) Lock() { … }
func (p T) Unlock() { … }
</pre>

<p>
they implement the <code>Locker</code> interface as well
as the <code>File</code> interface.

pkg sync, method (*WaitGroup) Done()
pkg sync, method (*WaitGroup) Wait()
pkg sync, type Cond struct
pkg sync, type Cond struct, L Locker
pkg sync, type Locker interface { Lock, Unlock }
pkg sync, type Locker interface, Lock()
pkg sync, type Locker interface, Unlock()
pkg sync, type Mutex struct
pkg sync, type Once struct
pkg sync, type RWMutex struct
pkg sync, type WaitGroup struct

[time.Timer] and [time.Ticker].

First, `Timer`s and `Ticker`s that are no longer referred to by the program
become eligible for garbage collection immediately, even if their
`Stop` methods have not been called.
Earlier versions of Go did not collect unstopped `Timer`s until after
they had fired and never collected unstopped `Ticker`s.

Second, the timer channel associated with a `Timer` or `Ticker` is

pkg testing, method (*B) TempDir() string
pkg testing, method (*T) Deadline() (time.Time, bool)
pkg testing, method (*T) TempDir() string
pkg testing, type TB interface, TempDir() string

to define an interface called <code>Locker</code>:
</p>

<pre>
type Locker interface {
	Lock()
	Unlock()
}
</pre>

<p>
If <code>S1</code> and <code>S2</code> also implement
</p>

<pre>
func (p T) Lock() { … }
func (p T) Unlock() { … }
</pre>

<p>
they implement the <code>Locker</code> interface as well
as the <code>File</code> interface.