Version bump to etcd v3.2.11

vendor/github.com/cockroachdb/cmux/buffer.go

@@ -0,0 +1,35 @@
+package cmux
+
+import (
+	"bytes"
+	"io"
+)
+
+// bufferedReader is an optimized implementation of io.Reader that behaves like
+// ```
+// io.MultiReader(bytes.NewReader(buffer.Bytes()), io.TeeReader(source, buffer))
+// ```
+// without allocating.
+type bufferedReader struct {
+	source     io.Reader
+	buffer     *bytes.Buffer
+	bufferRead int
+	bufferSize int
+}
+
+func (s *bufferedReader) Read(p []byte) (int, error) {
+	// Functionality of bytes.Reader.
+	bn := copy(p, s.buffer.Bytes()[s.bufferRead:s.bufferSize])
+	s.bufferRead += bn
+
+	p = p[bn:]
+
+	// Funtionality of io.TeeReader.
+	sn, sErr := s.source.Read(p)
+	if sn > 0 {
+		if wn, wErr := s.buffer.Write(p[:sn]); wErr != nil {
+			return bn + wn, wErr
+		}
+	}
+	return bn + sn, sErr
+}