v0.21.1

A server-thrown RpcError with no error_kind now reaches the client instead of hanging it.

Wire.errorMetadata wrote HasErrorKind.errorKind() into the error batch's metadata unconditionally, but that method returns null when no category applies — every RpcError built through the 3-arg constructor. The null threw in the flatbuffer key/value writer, so the error batch never reached the wire and the caller waited on a response that would never come.

🤖 Generated with Claude Code