Move the libs/pubsub package to internal scope (#7451)

No API changes, merely changes the import path.

internal/pubsub/example_test.go

@@ -0,0 +1,34 @@
+package pubsub_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	abci "github.com/tendermint/tendermint/abci/types"
+	"github.com/tendermint/tendermint/internal/pubsub"
+	"github.com/tendermint/tendermint/internal/pubsub/query"
+	"github.com/tendermint/tendermint/libs/log"
+)
+
+func TestExample(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s := newTestServer(ctx, t, log.TestingLogger())
+
+	sub := newTestSub(t).must(s.SubscribeWithArgs(ctx, pubsub.SubscribeArgs{
+		ClientID: "example-client",
+		Query:    query.MustCompile(`abci.account.name='John'`),
+	}))
+
+	events := []abci.Event{
+		{
+			Type:       "abci.account",
+			Attributes: []abci.EventAttribute{{Key: "name", Value: "John"}},
+		},
+	}
+	require.NoError(t, s.PublishWithEvents(ctx, "Tombstone", events))
+	sub.mustReceive(ctx, "Tombstone")
+}