v0.3.0

Changed

• Typed endpoints (breaking) — EndpointRequestBuilder from client.call::<E>() no longer has .param() / .query_pair(). Use .params(E::Params) and .query(E::Query) with typed structs (define_params!, impl_serde_endpoint_query!, or proc-macros). When E::Params is not (), .params() is required before .send_json(). Untyped client.get() / .post() are unchanged.
• Error::Transport — now { kind: TransportKind, message: String } instead of a plain String. Use Error::transport or Error::transport_message to construct transport errors.
• Error::RetryExhausted::last — now Option<Box<Error>> instead of Option<String> (preserves structured last failure).
• Transport mapping — map_transport_error classifies reqwest failures into TransportKind (Connect, Body, Decode, Redirect, Request, Builder, Upgrade, Other) in addition to the existing Timeout variant.

Added

• define_params!, extended endpoint!, impl_serde_endpoint_query! for typed path/query without proc-macros.
• Type-state builder — NeedsParams vs Ready on EndpointRequestBuilder.
• Proc-macros (feature macros) — EndpointParamsDerive, EndpointQueryDerive with path validation.
• serialize_to_query_map — serde structs to query params for OpenAPI/runtime parity.
• Streaming API — RequestBuilder::send_stream, StreamingResponse, HttpBackend::execute_stream, and BodyStream for incremental response bodies. max_response_bytes ends the stream after Error::BodyTooLarge (no infinite error loop).
• Streaming hooks — on_response_stream, on_success_stream, StreamingResponseContext, StreamingResponseMeta, StreamingSuccessContext (metadata only; buffered on_response / on_success are not called on the streaming path).
• Streaming retry peek — custom RetryPolicy::with_should_retry on send_stream can inspect up to retry_body_peek_bytes (default 64 KiB) of the body; status-only retries do not read the body.
• Streaming cancellation — CancelBodyStream registers the cancellation waker while the inner body read is pending.
• Tower streaming — ServiceBackend delegates execute_stream to a ReqwestBackend sharing the same reqwest::Client as the Tower stack (transport_stack wires this automatically).
• Error::BodyTooLarge — when a streaming response exceeds max_response_bytes.
• ClientBuilder::max_response_bytes / RequestBuilder::max_response_bytes — optional size cap on the streaming path.
• ClientBuilder::retry_body_peek_bytes / RequestBuilder::retry_body_peek_bytes — cap for retry predicate body peek on streams.
• Example — examples/streaming.rs; tests streaming_tests and streaming_tower_tests (feature tower).
• docs.rs — package.metadata.docs.rs with all-features, doc_cfg, and rustdoc example scraping.
• TransportKind — public enum for transport failure categories.
• Error::transport_kind, Error::transport_detail, Error::is_transport, Error::is_timeout, Error::retry_exhausted_last.
• CI — minimal feature-set checks (json + rustls-tls / native-tls, multipart).
• Release automation — .github/workflows/release.yml (tag v* → crates.io trusted publishing + GitHub Release from CHANGELOG.md).

Migration (0.2.x → 0.3.0)

• client.call::<E>() — replace .param("id", n) with .params(E::Params { ... }) (or define_params! / proc-macros). See README typed endpoint section.
• send() / send_json() — unchanged; still fully buffered.
• Custom HttpBackend — implement execute_stream (return an error if unsupported).
• Tower ServiceBackend — implement execute_stream on custom backends; with transport_stack, streaming uses the shared reqwest client (Tower middleware does not apply to send_stream).