streamdata: optionally reuse buffer

This enables use of stdlib iterator helpers.

Signed-off-by: Yonah <contrib@gensokyo.uk>

streamdata_test.go

@@ -303,7 +303,7 @@ func TestChannel(t *testing.T) {
 	}
 
 	var iterErr error
-	idents := slices.Collect(c.All(&iterErr))
+	idents := slices.Collect(c.All(&iterErr, false))
 	if iterErr != nil {
 		t.Fatalf("All: error = %#v", iterErr)
 	}