the type of the pointer.

Note that values of some Go types, other than the type's zero value,
always include Go pointers. This is true of string, slice, interface,
channel, map, and function types. A pointer type may hold a Go pointer
or a C pointer. Array and struct types may or may not include Go
pointers, depending on the element types. All the discussion below

	//
	// When Writer.WriteHeader is called, the contents of Xattrs will take
	// precedence over those in PAXRecords.
	//
	// Deprecated: Use PAXRecords instead.
	Xattrs map[string]string

	// PAXRecords is a map of PAX extended header records.
	//
	// User-defined records should have keys of the following form:
	//	VENDOR.keyword
	// Where VENDOR is some namespace in all uppercase, and keyword may

	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}
	fmt.Printf("%s\n", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
	// Output:
	// 'Gjnf oevyyvt naq gur fyvgul tbcure...
}

func ExampleReader_Len() {
	fmt.Println(bytes.NewReader([]byte("Hi!")).Len())

// (m[key]) from the map. If m is nil or there is no such element, delete
// is a no-op.
func delete(m map[Type]Type1, key Type)

// The len built-in function returns the length of v, according to its type:
//
//	Array: the number of elements in v.
//	Pointer to array: the number of elements in *v (even if v is nil).
//	Slice, or map: the number of elements in v; if v is nil, len(v) is zero.

	current     *apiPackage
	deprecated  map[token.Pos]bool
	features    map[string]bool              // set
	imported    map[string]*apiPackage       // packages already imported
	stdPackages []string                     // names, omitting "unsafe", internal, and vendored packages
	importMap   map[string]map[string]string // importer dir -> import path -> canonical path
	importDir   map[string]string            // canonical import path -> dir

	}, {
		header:  &Header{Xattrs: map[string]string{"foo": "bar"}},
		paxHdrs: map[string]string{paxSchilyXattr + "foo": "bar"},
		formats: FormatPAX,
	}, {
		header:  &Header{Xattrs: map[string]string{"foo": "bar"}, Format: FormatGNU},
		paxHdrs: map[string]string{paxSchilyXattr + "foo": "bar"},
		formats: FormatUnknown,
	}, {
		header:  &Header{Xattrs: map[string]string{"用戶名": "\x00hello"}},

		}
	}
	return hdr, &tr.blk, p.err
}

// readOldGNUSparseMap reads the sparse map from the old GNU sparse format.
// The sparse map is stored in the tar header if it's small enough.
// If it's larger than four entries, then one or more extension headers are used
// to store the rest of the sparse map.
//
// The Header.Size does not reflect the size of any extended headers used.

		tests: []testFnc{
			testHeader{Header{
				Typeflag: TypeReg,
				Name:     "file",
				Uname:    strings.Repeat("long", 10),
				PAXRecords: map[string]string{
					"path":           "FILE", // Should be ignored
					"GNU.sparse.map": "0,0",  // Should be ignored
					"comment":        "Hello, 世界",
					"GOLANG.pkg":     "tar",
				},
			}, nil},
			testClose{nil},
		},
	}, {

)

// Writer implements a zip file writer.
type Writer struct {
	cw          *countWriter
	dir         []*header
	last        *fileWriter
	closed      bool
	compressors map[uint16]Compressor
	comment     string

	// testHookCloseSizeOffset if non-nil is called with the size
	// of offset of the central directory at Close.
	testHookCloseSizeOffset func(size, offset uint64)
}

</p>

<h3 id="more">Additional Mechanisms</h3>

<p>
The <code>sync</code> package provides additional synchronization abstractions,
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.