v0.2.0

[0.2.0] - 2026-06-12: response and trailer metadata on the builder, trailer assertions

Minor release. Lets a faked call carry response headers and trailers, and adds trailer assertions (text and binary) to the RpcException chain. Purely additive.

Added

• GrpcCallBuilder.Success<T>(T response, Metadata? responseHeaders, Metadata? trailers) and GrpcCallBuilder.Faulted<T>(StatusCode statusCode, string? detail, Metadata trailers) build calls that carry response metadata, so a wrapper that reads response headers or trailers can be tested against a fake. A null headers or trailers argument is treated as empty metadata.
• WithTrailer(string key, string value) and WithTrailer(string key, ReadOnlySpan<byte> value) on the ThrowsGrpcException() chain assert the exception's Trailers contain a text or binary (-bin) entry. Keys are matched case-insensitively (gRPC lowercases metadata keys). The text overload reads Metadata.Entry.Value and the binary overload reads Metadata.Entry.ValueBytes, each guarded by Entry.IsBinary, so the value of a binary entry is never read as a string. On failure the message renders the trailers, with binary entries shown as (binary, N bytes).

Fixed

• GrpcCallBuilder.Success<T> now returns the same trailers Metadata instance on every call to the trailers accessor, matching a real client; it previously returned a fresh empty Metadata each time, so an identity check or mutation did not behave as it would against a real call.

Changed

• README adds an "Await the call against a generated client" note: a generated client's XAsync returns AsyncUnaryCall<T> whose fault lives in ResponseAsync, so a delegate that returns the call without awaiting it never surfaces the fault and the assertion reports no exception. Assert via async () => await client.XAsync(...) or client.XAsync(...).ResponseAsync when testing a raw generated client; wrapper tests, which return Task, are unaffected.
• Bumped PackageValidationBaselineVersion from 0.1.1 to 0.1.2 on both packages so ApiCompat strict-mode validates 0.2.0 against the most recently published baseline. The new overloads are recorded as additive differences in CompatibilitySuppressions.xml.