Added performant in-process message broker to data's routing subpackage

pkg/data/routing/interfaces.go

@@ -0,0 +1,25 @@
+package routing
+
+import (
+	"context"
+
+	"gitlab.michelsen.id/phillmichelsen/tessera/pkg/data"
+)
+
+// Publisher is the write-side handle given to data sources.
+type Publisher interface {
+	Publish(env data.Envelope)
+}
+
+// Subscriber is the read-side handle given to consumers (data sinks).
+type Subscriber interface {
+	// Receive blocks until a message is available or the context cancels.
+	// Best for general low-latency consumers that shouldn't burn CPU.
+	// Typically more than enough for most situations
+	Receive(ctx context.Context) (data.Envelope, error)
+
+	// TryReceive attempts to read one message lock-free.
+	// Returns (envelope, true, nil) if successful, or false if nothing is available.
+	// Polling TryReceive without a wait will most likely spike the CPU
+	TryReceive() (data.Envelope, bool, error)
+}