add server Context option to pass own context

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

server/options.go

@@ -136,6 +136,15 @@ func Codec(contentType string, c codec.NewCodec) Option {
 	}
 }
 
+// Context specifies a context for the service.
+// Can be used to signal shutdown of the service
+// Can be used for extra option values.
+func Context(ctx context.Context) Option {
+	return func(o *Options) {
+		o.Context = ctx
+	}
+}
+
 // Registry used for discovery
 func Registry(r registry.Registry) Option {
 	return func(o *Options) {