fix example and e2e test

test/e2e/discard_writer.go

@@ -0,0 +1,11 @@
+package e2e
+
+import "io"
+
+var discardWriter io.Writer = discard{}
+
+type discard struct{}
+
+func (d discard) Write(p []byte) (n int, err error) {
+	return len(p), nil
+}