[christopherread]

Fixes #78. Merge after #82: this branch is built on it so CI can run the NATS tests against a real server, and the diff includes #82's commits until it merges.

Changes

• Package: NATS.Client 1.1.8 (legacy) → NATS.Client.Core 3.3.1, the core client of NATS.Net. I used it instead of the NATS.Net meta-package because Obvs doesn't need JetStream, key-value or object store. It supports net472 (via netstandard2.0), netstandard2.1 and net10.0.
• MessagePublisher: awaits PublishAsync on the connection. Before, it published synchronously and returned a completed task.
• MessageSource: subscribes with SubscribeCoreAsync and reads the subscription's message channel on a background task.
  • Subscribe still blocks until the server has the subscription, as with 1.x, so messages published straight after it aren't missed.
  • Processing errors still go to OnError.
  • Disposing unsubscribes.
• Connections: SharedConnectionFactory creates a NatsConnection(new NatsOpts { Url }) per URL; it connects on first use, as the Lazy connections did. Endpoint disposal disposes the connection, as before.
• C# version: Obvs.NATS compiles as C# 9, because NatsOpts has init-only properties and net472/netstandard2.0 default to C# 7.3. It's compiler-only; there's no runtime requirement.
• Analyzer warnings: NATS.Net brings in the VS threading analyzers. The deliberate sync waits (Subscribe and Dispose are synchronous in Obvs) are suppressed with a comment. The fire-and-forget receive task is explicitly discarded; it reports its own failures to the observer.

Wire format unchanged

Messages still carry the protobuf MessageWrapper envelope (properties + body) on subjects <prefix>.<TypeName>. So services on old and new Obvs.NATS versions can exchange messages. NATS headers would be the modern alternative, but switching would break mixed deployments.

⚠️ Breaking changes for consumers

• Fluent configuration (WithNatsEndpoint(settings => …), Url, IsShared, message properties): unchanged.
• Direct use of MessageSource and MessagePublisher: the constructors take an INatsConnection instead of Lazy<IConnection>. For example: new MessageSource<T>(new NatsConnection(new NatsOpts { Url = url }), …).
• The NATS.Client dependency is gone. Code that uses its types alongside Obvs.NATS needs NATS.Net.

Testing

I made the tests check outcomes first, then compared the old and new client in CI against a real nats:2.15 server:

• TestSourceAndPublisher: all 10 messages arrive, in order. It previously only printed them.
• TestServiceBus: the reply arrives with the right Id, and the command's event is received. It previously only printed.

	NATS.Client 1.1.8 (first commit)	NATS.Net 3.3.1 (this PR)
NATS broker tests	✅ 2/2	✅ 2/2

RabbitMQ (3) and Kafka (1) broker tests also pass in both runs. The solution builds for all targets with no new warnings, and all unit tests pass.

🤖 Generated with Claude Code

[christopherread]

Combined into #104, which includes this change as its own commit.