Add capnp-rpc-lwt compatibility package

This allows existing libraries using capnp-rpc-lwt to be used with
applications using Eio, easing the transition.

.github/workflows/main.yml

@@ -22,7 +22,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Use OCaml ${{ matrix.ocaml-compiler }}
         uses: ocaml/setup-ocaml@v3

CHANGES.md

@@ -1,3 +1,29 @@
+### v2.x
+
+- Rename `Capnp_rpc_lwt` to `Capnp_rpc` (which is now `Capnp_rpc_proto`).
+  The new `Capnp_rpc` now provides `Error`, `Exception` and `Debug` aliases
+  to the same modules in `Capnp_rpc_proto`, so that `Capnp_rpc_proto` doesn't
+  need to be used directly.
+
+- Add `Capnp_rpc.Std` with some common module aliases, to reduce the need
+  to `open Capnp_rpc` (which is rather large).
+
+- Convert API from Lwt to Eio.
+
+To update to the new API:
+
+1. Use [lwt_eio][] during the migration to allow using Eio and Lwt together in your application.
+2. Replace `open Capnp_rpc_lwt` with `open Capnp_rpc.Std`.
+3. Replace all other uses of `Capnp_rpc_lwt` with just `Capnp_rpc`.
+4. In `dune` and `opam` files, replace `capnp-rpc-lwt` with `capnp-rpc`.
+5. Some modules are in `Capnp_rpc` but not the `Capnp_rpc.Std` subset.
+   Those should now be fully qualified (e.g. replace `Persistence` with
+   `Capnp_rpc.Persistence`).
+6. Replace `Service.return_lwt` with `Lwt_eio.run_lwt`.
+7. Once all Lwt code is gone, `lwt_eio` can be removed.
+
+[lwt_eio]: https://github.com/ocaml-multicore/lwt_eio
+
 ### v1.2.3
 
 - Update to cmdliner 1.1.0 (@MisterDA #249).

Makefile

@@ -2,11 +2,6 @@
 
 default: test build-fuzz
 
-all:
-	dune build @install test/test.exe test-lwt/test_lwt.exe test-bin/calc.exe
-	rm -rf _build/_tests
-	dune runtest --no-buffer -j 1
-
 build-fuzz:
 	dune build fuzz/fuzz.exe
 
@@ -19,7 +14,5 @@ clean:
 
 test:
 	rm -rf _build/_tests
-	dune build test/test.exe test-lwt/test_lwt.exe test-bin/calc.exe test-bin/echo/echo_bench.exe @install
-	#./_build/default/test/test.bc test core -ev 36
-	#./_build/default/test-lwt/test.bc test lwt -ev 3
+	dune build test test-bin @install
 	dune build @runtest --no-buffer -j 1