document shared pool expected

Makefile

@@ -20,6 +20,9 @@ cover: .cover
 showcover: .cover
 	go tool cover -html .cover
 
+bench: $(sources)
+	go test -bench Benchmark -run ^$
+
 clean:
 	go clean
 	rm .cover

lib.go

@@ -26,7 +26,9 @@ type Pool interface {
 // Options provides options for the Reader.
 type Options struct {
 
-	// Pool defines the buffer pool to be used. It defaults to the pool created by DefaultPool().
+	// Pool defines the buffer pool to be used. It defaults to the pool created by DefaultPool(). It is
+	// expected to explicitly set the Pool instance, otherwise, not defining any globals, each Reader
+	// instance will create its own pool.
 	Pool Pool
 }
 

lib_test.go

@@ -1,6 +1,7 @@
 package buffer_test
 
 import (
+	"bufio"
 	"bytes"
 	"code.squareroundforest.org/arpio/buffer"
 	"errors"
@@ -150,3 +151,46 @@ func TestLib(t *testing.T) {
 		})
 	})
 }
+
+// -- bench
+
+type readerOnly struct {
+	in io.Reader
+}
+
+type writerOnly struct {
+	in io.Writer
+}
+
+func (r readerOnly) Read(p []byte) (int, error) {
+	return r.in.Read(p)
+}
+
+func (w writerOnly) Write(p []byte) (int, error) {
+	return w.in.Write(p)
+}
+
+func BenchmarkThroughput(b *testing.B) {
+	p := buffer.DefaultPool(0)
+	dst := bytes.NewBuffer(nil)
+	wo := writerOnly{dst}
+	for i := 0; i < b.N; i++ {
+		src := bytes.NewBuffer(make([]byte, 1<<18))
+		r := buffer.BufferedReader(src, buffer.Options{Pool: p})
+		ro := readerOnly{r}
+		dst.Reset()
+		io.Copy(wo, ro)
+	}
+}
+
+func BenchmarkCompare(b *testing.B) {
+	dstBuf := bytes.NewBuffer(nil)
+	dst := writerOnly{dstBuf}
+	for i := 0; i < b.N; i++ {
+		srcBuf := bytes.NewBuffer(make([]byte, 1<<18))
+		srcReader := bufio.NewReader(srcBuf)
+		src := readerOnly{srcReader}
+		dstBuf.Reset()
+		io.Copy(dst, src)
+	}
+}