v0.4.0

Added

• Streaming uploads — RequestBuilder::body_stream and Error::NonReplayableBody when retry cannot replay the body.
• Tower dual stack — ClientBuilder::transport_stack wires separate buffered and streaming transports; use this when middleware must apply to send_stream().
• Strict JSON Schema (feature schema-validate) — optional validation of request/response JSON, query, and path params when the registry is strict; stream responses validate on collect().
• Garde validation (feature validate) — json_validated, query_validated, with_headers_validated on builders.
• Typed endpoint macros — #[derive(Endpoint)] with #[param], #[query_field], #[query], #[endpoint(register)], and NeedsBody for POST bodies.
• SSE — incremental SseDecoder and StreamingResponse::sse_events().
• API helpers — into_api_result / send_api, ResponseBodyKind, RecordingBackend for tests, better_fetch::prelude, RequestBuilder::base_url.
• Features — full, miette (DiagnosticError), otel (OpenTelemetry re-exports for tracing subscribers).
• Errors — QuerySerialize, RequestValidation, SchemaValidation, InvalidHeaderName / InvalidHeaderValue, MissingPathParam, SchemaRoute, Transport::source, and clearer Io / Config.
• Docs — testing, observability, ROADMAP; publishing notes in README.

Changed

• Breaking: typed .query(...) and EndpointQuery::apply_query return Result; serialization errors become Error::QuerySerialize.
• Breaking: ClientConfig::hooks is private; use ClientConfig::effective_hooks().
• Breaking: EndpointRequestBuilder implements Deref only (no DerefMut); use typed .query(MyQuery)? instead of stringly .query("key", "value") on ready builders.
• Breaking: transport_stack takes (buffered, streaming) and returns two boxed services.
• Breaking: impl Endpoint requires Body and Headers associated types (often ()).
• Breaking: Error::Transport carries an optional source; Error::RetryExhausted::last is Option<Box<Error>>.
• Hooks on streams — on_error runs for failed send_stream() responses even without throw_on_error, matching buffered behavior.
• http_service / http_service_boxed — documented: Tower layers apply to buffered send() only; streaming still uses reqwest unless you use transport_stack.
• LoggerPlugin — richer tracing (http.request / http.response, retry attempt, error body preview).
• Retry — shared buffered/streaming retry loop; aligned backoff, cancellation, and throw_on_error body handling.

Fixed

• on_request hooks — changes to RequestContext::body are applied to the outgoing request.
• throw_on_error + send_stream — HTTP errors include a peeked body when possible.
• Query in path templates — ?foo=bar in the path merges with builder query (builder wins).
• Stream limits — max_response_bytes applies to collect(), stream_to_file, and SSE helpers when set on the client or request.

Migration (0.3.x → 0.4.0)

• Add ? after typed .query(...).
• Replace config().hooks with config().effective_hooks().
• Replace into_inner() with Deref or delegated builder methods.
• Do not use stringly .query("k", "v") on client.call::<E>() after params are set.
• For Tower on both send() and send_stream(), use transport_stack, not http_service alone.
• Add type Body = (); type Headers = (); to manual Endpoint impls if missing.
• Multipart or streaming upload retry may return Error::NonReplayableBody instead of a generic error.