Extending the Istio data plane using Wasm

The main goal for Wasm was to enable high-performance applications on web pages, and hence Wasm was originally designed for execution in web browsers. There is a World Wide Web Consortium (W3C) working group for Wasm, whose details are available at https://www.w3.org/Wasm/. The working group manages the Wasm specification available at https://www.w3.org/TR/Wasm-core-1/ and https://www.w3.org/TR/Wasm-core-2/. Most internet browsers have implemented the specification, and you can find details for Google Chrome at https://chromestatus.com/feature/5453022515691520. Mozilla Foundation also maintains browser compatibility at https://developer.mozilla.org/en-US/docs/WebAssembly#browser_compatibility. When it comes to supporting the execution of Wasm on layer 4 and 7 proxies, most of the effort is recent. When executing Wasm on proxies, we need a way to communicate with the host environment. Similar to how web browsers are developed, Wasm should be...