wasn't a caching issue, I'm not sure

.github/workflows/ci.yml

@@ -220,6 +220,14 @@ jobs:
           profile: minimal
           toolchain: stable
           override: true
+
+      - name: Save sccache
+        uses: actions/cache@v2
+        continue-on-error: false
+        with:
+          path: /home/runner/.cache/sccache
+          key: ubuntu-sccache-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: ubuntu-sccache-
             
       - name: Start sccache server
         run: sccache --start-server
@@ -243,9 +251,24 @@ jobs:
     runs-on: ubuntu-latest
     env:
       RUSTC_BOOTSTRAP: 1
+      RUSTC_WRAPPER: sccache
+      SCCACHE_CACHE_SIZE: 2G
+      SCCACHE_DIR: /home/runner/.cache/sccache
     steps:
       - name: Checkout
         uses: actions/checkout@v1
+
+      - name: Install sccache Ubuntu
+        env:
+          LINK: https://github.com/mozilla/sccache/releases/download
+          SCCACHE_VERSION: v0.2.15
+        run: |
+          SCCACHE_FILE=sccache-$SCCACHE_VERSION-x86_64-unknown-linux-musl
+          mkdir -p $HOME/.local/bin
+          curl -L "$LINK/$SCCACHE_VERSION/$SCCACHE_FILE.tar.gz" | tar xz
+          mv -f $SCCACHE_FILE/sccache $HOME/.local/bin/sccache
+          chmod +x $HOME/.local/bin/sccache
+          echo "$HOME/.local/bin" >> $GITHUB_PATH
         
       - name: Install Rust
         uses: actions-rs/toolchain@v1
@@ -255,6 +278,30 @@ jobs:
           override: true
           components: rustfmt
 
+      - name: Cache cargo registry
+        uses: actions/cache@v2
+        continue-on-error: false
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+          key: codecov-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            codecov-cargo-
+            
+      - name: Save sccache
+        uses: actions/cache@v2
+        continue-on-error: false
+        with:
+          path: /Users/runner/Library/Caches/Mozilla.sccache
+          key: codecov-sccache-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            codecov-sccache-
+            
+      - name: Start sccache server
+        run: |
+          sccache --start-server
+
       - name: Test
         uses: actions-rs/cargo@v1
         with:
@@ -284,4 +331,10 @@ jobs:
         uses: codecov/codecov-action@v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
-          token: ${{ secrets.CODECOV_TOKEN }}
+          token: ${{ secrets.CODECOV_TOKEN }}
+
+      - name: Print sccache stats
+        run: sccache --show-stats
+        
+      - name: Stop sccache server
+        run: sccache --stop-server || true