Stream operations can be defined ostensibly in any lang. that compiles to wasm, enabling polyglot stream processing.
Wasm component model enables the stream processing operations to be natively available to wasm compatible languages.
Fluvio core streaming engine is implemented in Rust.
The first generation stream processing, transformations were initially implemented in Rust needed binding generators to work in Python, JavaScript, Go etc. Also state and window operations and offset management needed to be expressed in application logic.
In the current generation of stream processing wasm component model enables a native support for polyglot stream processing.