ADR 0001: HTTPX2 transport boundary

Context

The SDK needs pooling, streaming, timeouts, injection, sync/async parity, and testable retries.

Decision

All remote access crosses provider-neutral HTTPX2 sync or async transports.

Alternatives

Direct calls in fetchers and multiple HTTP libraries were considered.

Consequences

Providers construct requests but never own clients or retry loops.

Rejected shortcuts

Per-call clients, implicit global clients, and mixed HTTP dependencies are rejected.

Operational implications

Applications tune four timeouts, pools, TLS, proxy, HTTP/2, rate, hooks, and bounded retries.