Add Inner Ring code

pkg/morph/event/handler.go

@@ -0,0 +1,23 @@
+package event
+
+// Handler is an Event processing function.
+type Handler func(Event)
+
+// HandlerInfo is a structure that groups
+// the parameters of the handler of particular
+// contract event.
+type HandlerInfo struct {
+	scriptHashWithType
+
+	h Handler
+}
+
+// SetHandler is an event handler setter.
+func (s *HandlerInfo) SetHandler(v Handler) {
+	s.h = v
+}
+
+// Handler returns an event handler.
+func (s HandlerInfo) Handler() Handler {
+	return s.h
+}