Quan Hoang enhanced the Thrift client in the facebook/fbthrift repository by implementing header propagation and improved response handling for RPC calls. He consolidated the client’s API around genAwaitResponse, removing legacy paths such as genAwaitResponseWithReadHeaders to streamline maintenance and usage. By extending header support to asynchronous calls and updating the internal Hack-based compiler, Quan enabled end-to-end observability and tracing of server-provided headers. His work, primarily using PHP, Hack, and Thrift, focused on backend development and testing, resulting in a more interoperable and maintainable client. The changes addressed both technical debt and feature gaps in header management for RPC workflows.