pkg, _ := w.import_(name)
				w.export(pkg)
			}
			w.Features()
		}
	}
}

var warmupCache = sync.OnceFunc(func() {
	// Warm up the import cache in parallel.
	var wg sync.WaitGroup
	for _, context := range contexts {
		context := context
		wg.Add(1)
		go func() {
			defer wg.Done()
			_ = NewWalker(context, filepath.Join(testenv.GOROOT(nil), "src"))
		}()
	}
	wg.Wait()
})

	"net/http"
	"os"
	"regexp"
	"strings"
	"sync"
)

var (
	root    = flag.String("root", "http://localhost:6060", "Root to crawl")
	verbose = flag.Bool("verbose", false, "verbose")
)

var wg sync.WaitGroup        // outstanding fetches
var urlq = make(chan string) // URLs to crawl

// urlFrag is a URL and its optional #fragment (without the #)
type urlFrag struct {
	url, frag string
}

var (

		}
	}
}

func TestReaderAtConcurrent(t *testing.T) {
	// Test for the race detector, to verify ReadAt doesn't mutate
	// any state.
	r := NewReader([]byte("0123456789"))
	var wg sync.WaitGroup
	for i := 0; i < 5; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			var buf [1]byte
			r.ReadAt(buf[:], int64(i))
		}(i)
	}
	wg.Wait()
}

pkg sync, method (*RWMutex) RLock()
pkg sync, method (*RWMutex) RLocker() Locker
pkg sync, method (*RWMutex) RUnlock()
pkg sync, method (*RWMutex) Unlock()
pkg sync, method (*WaitGroup) Add(int)
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()

		if err != nil {
			t.Fatal(err)
		}
		nextFiles = next
	}

	for _, c := range contexts {
		c.Compiler = build.Default.Compiler
	}

	walkers := make([]*Walker, len(contexts))
	var wg sync.WaitGroup
	for i, context := range contexts {
		i, context := i, context
		wg.Add(1)
		go func() {
			defer wg.Done()
			walkers[i] = NewWalker(context, filepath.Join(testenv.GOROOT(t), "src"))
		}()
	}

including <a href="/pkg/sync/#Cond">condition variables</a>,
<a href="/pkg/sync/#Map">lock-free maps</a>,
<a href="/pkg/sync/#Pool">allocation pools</a>,
and
<a href="/pkg/sync/#WaitGroup">wait groups</a>.
The documentation for each of these specifies the guarantees it
makes concerning synchronization.
</p>

<p>
Other packages that provide synchronization abstractions