Continued scaffolding and interface definitions

services/data_service/internal/node/sink/sink.go

@@ -0,0 +1,17 @@
+// Package sink
+package sink
+
+import (
+	"context"
+
+	"gitlab.michelsen.id/phillmichelsen/tessera/services/data_service/internal/node"
+)
+
+type Sink interface {
+	Start(ctx context.Context, io IO) error
+	Stop()
+}
+
+type IO interface {
+	node.Sender
+}