internal/server/server.go: Implement options using the functional pattern.

cmd/antelope-api-healtcheck/main.go

@@ -181,7 +181,7 @@ func main() {
 	}
 
 	// Create server
-	srv = server.New(argv_listen_addr(), time.Second*10)
+	srv = server.New(argv_listen_addr(), server.WithTick(time.Second*10))
 
 	// Run signal event loop in its own goroutine
 	go signalEventLoop()

internal/server/server.go

@@ -28,10 +28,23 @@ type Server struct {
 	tick_interval time.Duration
 }
 
-func New(addr string, tick_interval time.Duration) *Server {
-	return &Server{
+type Option func(*Server)
+
+func New(addr string, options ...Option) *Server {
+	s := &Server{
 		addr: fmt.Sprintf("tcp://%s", addr),
-		tick_interval: tick_interval,
+	}
+
+	for _, opt := range options {
+		opt(s)
+	}
+
+	return s
+}
+
+func WithTick(interval time.Duration) Option {
+	return func(s *Server) {
+		s.tick_interval = interval
 	}
 }