func (s Status) IsSent() bool {
	switch s {
	case StatusQueuedRemotely, StatusDelivered, StatusSent:
		return true
	}
	return false
}
IsSent returns true if the message has been successfully sent to the downstream server.
package message
type Status string
const (
	StatusPending = Status("pending")
	StatusSending = Status("sending")
	StatusQueuedRemotely = Status("queued_remotely")
	StatusSent = Status("sent")
	StatusDelivered = Status("delivered")
	StatusFailed = Status("failed")
	StatusStale = Status("stale")
)