Add stress test (#3222)

Created a simple echo TCP server that on two different runtimes that is
called from a GitHub action using Valgrind to ensure that there are
no memory leaks.

Fixes: #3022

.github/workflows/stress-test.yml

@@ -0,0 +1,29 @@
+name: Stress Test
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  stess-test:
+    name: Stress Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        stress-test:
+          - simple_echo_tcp
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install Rust
+        run: rustup update stable
+
+      - name: Install Valgrind
+        run: apt install -y valgrind
+
+      # Compiles each of the stress test examples.
+      - name: Compile stress test examples
+        run: cargo build -p stress-test --release --examples ${{ matrix.stress-test }}
+
+      # Runs each of the examples using Valgrind. Detects leaks and displays them.
+      - name: Run valgrind
+        run: valgrind  --leak-check=full --show-leak-kinds=all ./target/release/${{ matrix.stress-test }}