Added TimeoutReader

Fixes #1.

trash.go

@@ -1,6 +1,10 @@
+// Package trash provides simple readers with meaningless output.
 package trash
 
-import "io"
+import (
+	"io"
+	"time"
+)
 
 func init() {
 	Reader = &reader{}
@@ -9,13 +13,36 @@ func init() {
 // Reader provides a steady stream of trash (non-random bytes) when read from
 var Reader io.Reader
 
+// TimeoutReader returns a reader that returns io.EOF after dur.
+func TimeoutReader(dur time.Duration) io.Reader {
+	return &timeoutReader{timeout: time.Now().Add(dur)}
+}
+
 type reader struct{}
 
 func (r *reader) Read(p []byte) (int, error) {
 	c := 0
+	var err error
 	for i := 0; i < len(p); i++ {
 		c++
 		p[i] = 0xca
 	}
-	return c, nil
+	return c, err
+}
+
+type timeoutReader struct {
+	timeout time.Time
+}
+
+func (tor *timeoutReader) Read(p []byte) (int, error) {
+	c := 0
+	var err error
+	for i := 0; i < len(p); i++ {
+		c++
+		p[i] = 0xca
+	}
+	if time.Now().After(tor.timeout) {
+		err = io.EOF
+	}
+	return c, err
 }