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An opaque NATS server endpoint.

Keeping this representation private allows endpoint schemes and transports to be added without changing the connection API.

Construct a TCP NATS server endpoint.

Construct a server using the standard NATS port, 4222.

Connect to one of the configured NATS servers.

Compatibility connection entry point using raw (host, port) tuples.

Fetch a token for every connection and reconnection attempt.

Fetch a username and password for every connection and reconnection attempt.

Authenticate with a public NKey and a handler that signs the server nonce. The handler returns the raw 64-byte Ed25519 signature; natskell performs the protocol's base64url encoding.

Fetch a user JWT and sign the server nonce for every connection attempt.

Require TLS using the operating system trust store.

Trust a PEM-encoded root certificate for this client. Once configured, these roots replace the operating-system trust store for the connection.

Override the host name used for certificate verification and SNI.

Disable server certificate verification. This is unsafe and should only be used when the peer is trusted by some mechanism outside TLS.

Set the total time budget for TCP acquisition, INFO, TLS, CONNECT, PONG, and reconnect resubscription/readiness on each server attempt. Values below one microsecond are clamped to one.

Set the largest encoded message body this client accepts. For messages with headers, the encoded header block and payload both count toward the limit. Outbound messages are also constrained by the server's max_payload.

Bound callback deliveries pending across the entire client. The first limit is a message count and the second is encoded message bytes.

Receive asynchronous client errors such as slow-consumer notifications. The handler runs on the callback worker pool, never the socket reader.

Receive protocol -ERR values on a bounded, dedicated serial worker. Protocol processing, including PONG handling, does not wait for the handler.

Receive completed disconnect, reconnect, and close transitions on the same serial callback worker as server errors. Lifecycle delivery is reserved independently from the bounded server-error backlog.

Compatibility alias for withMessageLimit.