move the functional option into option.go

option.go

@@ -0,0 +1,22 @@
+package udpproxy
+
+import (
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// Option is a functional option type that allows us to configure the Client.
+type Option func(*Client)
+
+// WithSessionTimeout is a functional option to set the session timeout
+func WithSessionTimeout(timeout time.Duration) Option {
+	return func(c *Client) {
+		if timeout < time.Minute {
+			log.Warnf("cannot set stale session timeout to less than 1 minute.. defaulting to 20 minutes")
+			return
+		}
+
+		c.sessionTimeout = timeout
+	}
+}