Iterative Optimization on Hot Paths: Optimization 2: Cutting out the middleman

scanner.go.diff

// goodbye reflect.New in Scanner.Scan
func (s *Scanner) Scan(src interface{}) error {
-	s.value = reflect.New(s.Type)
+	// Clear out the value after a scan so we aren't holding onto references.
+	defer func() { s.value = reflect.Value{} }()
	// ...
}

// and hello Scanner.Target
+func (s *Scanner) Target(value reflect.Value) {
+	s.value = value
+}