kubernetes/vendor/go.uber.org/zap/zapcore/write_syncer.go

type WriteSyncer …

// AddSync converts an io.Writer to a WriteSyncer. It attempts to be
// intelligent: if the concrete type of the io.Writer implements WriteSyncer,
// we'll use the existing Sync method. If it doesn't, we'll add a no-op Sync.
func AddSync(w io.Writer) WriteSyncer { … }

type lockedWriteSyncer …

// Lock wraps a WriteSyncer in a mutex to make it safe for concurrent use. In
// particular, *os.Files must be locked before use.
func Lock(ws WriteSyncer) WriteSyncer { … }

func (s *lockedWriteSyncer) Write(bs []byte) (int, error) { … }

func (s *lockedWriteSyncer) Sync() error { … }

type writerWrapper …

func (w writerWrapper) Sync() error { … }

type multiWriteSyncer …

// NewMultiWriteSyncer creates a WriteSyncer that duplicates its writes
// and sync calls, much like io.MultiWriter.
func NewMultiWriteSyncer(ws ...WriteSyncer) WriteSyncer { … }

// See https://golang.org/src/io/multi.go
// When not all underlying syncers write the same number of bytes,
// the smallest number is returned even though Write() is called on
// all of them.
func (ws multiWriteSyncer) Write(p []byte) (int, error) { … }

func (ws multiWriteSyncer) Sync() error { … }