// send push message
msg := fcm.NewMessage("/topics/all").SetPriority(fcm.High)
c := fcm.NewClient("<YOUR SERVER KEY>")
resp, _ := c.Send(msg)
fmt.Println(resp)
// get regitration token info
respInfo, _ := c.GetRegistrationTokenInfo("<REGISTRATION TOKEN>")
fmt.Println(respInfo)
go get github.com/kwmt/fcm