Fixing CI action, MSRV needed to be bumped for async-std runtime only

Author: Andrew J Westlake

.github/workflows/ci.yml

@@ -57,11 +57,16 @@ jobs:
           - python-version: pypy-3.6
             platform: { os: "windows-latest", python-architecture: "x64" }
         include:
-          # Test minimal supported Rust version
+          # Test minimal supported Rust version (no async-std)
           - rust: 1.45.0
             python-version: 3.9
             platform: { os: "ubuntu-latest", python-architecture: "x64", rust-target: "x86_64-unknown-linux-gnu" }
             msrv: "MSRV"
+          # Test minimal supported Rust version (with async-std)
+          - rust: 1.46.0
+            python-version: 3.9
+            platform: { os: "ubuntu-latest", python-architecture: "x64", rust-target: "x86_64-unknown-linux-gnu" }
+            msrv: "MSRV"
 
     steps:
       - uses: actions/checkout@v2
@@ -87,13 +92,22 @@ jobs:
       - name: Build (no features)
         run: cargo build --no-default-features --verbose --target ${{ matrix.platform.rust-target }}
 
+      - name: Set variables
+        id: setvars
+        run: |
+          if [[ "${{matrix.rust}} == "1.45.0" ]]; then
+            echo "::set-env name=features::testing,attributes,tokio-runtime"
+          else
+            echo "::set-env name=features::testing,attributes,tokio-runtime,async-std-runtime"
+          fi
+
       - name: Build (all additive features)
-        run: cargo build --all-features --verbose --target ${{ matrix.platform.rust-target }}
+        run: cargo build --features=$features --verbose --target ${{ matrix.platform.rust-target }}
 
       # Run tests (except on PyPy, because no embedding API).
       - if: matrix.python-version != 'pypy-3.6'
         name: Test
-        run: cargo test --all-features --target ${{ matrix.platform.rust-target }}
+        run: cargo test --features=$features --target ${{ matrix.platform.rust-target }}
 
       - name: Install python test dependencies
         run: |

README.md

@@ -3,7 +3,7 @@
 [![Actions Status](https://github.com/awestlake87/pyo3-asyncio/workflows/CI/badge.svg)](https://github.com/awestlake87/pyo3-asyncio/actions)
 [![codecov](https://codecov.io/gh/awestlake87/pyo3-asyncio/branch/master/graph/badge.svg)](https://codecov.io/gh/awestlake87/pyo3-asyncio)
 [![crates.io](http://meritbadge.herokuapp.com/pyo3-asyncio)](https://crates.io/crates/pyo3-asyncio)
-[![minimum rustc 1.45](https://img.shields.io/badge/rustc-1.45+-blue.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
+[![minimum rustc 1.46](https://img.shields.io/badge/rustc-1.46+-blue.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
 
 [Rust](http://www.rust-lang.org/) bindings for [Python](https://www.python.org/)'s [Asyncio Library](https://docs.python.org/3/library/asyncio.html). This crate facilitates interactions between Rust Futures and Python Coroutines and manages the lifecycle of their corresponding event loops.
 
@@ -183,4 +183,9 @@ Type "help", "copyright", "credits" or "license" for more information.
 
 > Note that we are using `EventLoop.run_until_complete` here instead of the newer `asyncio.run`. That is because `asyncio.run` will set up its own internal event loop that `pyo3_asyncio` will not be aware of. For this reason, running `pyo3_asyncio` conversions through `asyncio.run` is not currently supported.
 > 
-> This restriction may be lifted in a future release.
+> This restriction may be lifted in a future release.
+
+## MSRV
+Currently the MSRV for this library is 1.46.0, _but_ if you don't need to use the `async-std-runtime`
+feature, you can use rust 1.45.0. 
+> `async-std` depends on `socket2` which fails to compile under 1.45.0.