docs: update index

docs/pages/index.mdx

@@ -18,4 +18,19 @@ zig-aio provides io_uring like asynchronous API and coroutine powered IO tasks f
 - Cancellation
 - Timeouts
 - Comes with a runtime and scheduler for coroutines
-- Tightly tied into io_uring
+- Portable high precision timers compatible with `io_uring` `timeout`
+- Tightly tied into `io_uring` by providing compatible API
+
+## Support matrix
+
+| OS      | AIO             | CORO            |
+|---------|-----------------|-----------------|
+| Linux   | io_uring, posix | x86_64, aarch64 |
+| Windows | iocp            | x86_64, aarch64 |
+| *BSD    | posix           | x86_64, aarch64 |
+| WASI    | posix           | ❌              |
+
+* io_uring AIO backend is very light wrapper, where all the code does is mostly error mapping
+* iocp also maps quite well to the io_uring style API
+* posix backend is for compatibility, it may not be very effecient
+* WASI may eventually get coro support [Stack Switching Proposal](https://github.com/WebAssembly/stack-switching/blob/main/proposals/continuations/Explainer.md)