[.NET] Add Performance Testing Workflow for Lambda Layer (#393)

**Issue description:**
Added a workflow to automatically performance test and gather the
results for the unreleased .NET Lambda Layer.

**The GitHub workflow does the following:**
1. Deploy and setup the .NET Lambda sample application instrumented with
the Application Signals Lambda Layer on the AppSignals e2e testing aws
account.
2. Record the start time of the test and run the specified amount
(default: 20) Lambda cold start iterations on the sample application
3. Record the end time of the test
4. Query CW Logs Insights for the aggregated performance testing metrics
with the following query:
```
fields @timestamp, @message, @initDuration
| filter @message like "REPORT RequestId"
| stats
    count(@initDuration) as Sample_Count,
    avg(@initDuration) as Average_Init_Duration,
    min(@initDuration) as Min_Init_Duration,
    max(@initDuration) as Max_Init_Duration,
    pct(@initDuration, 50) as P50_Init_Duration,
    pct(@initDuration, 90) as P90_Init_Duration,
    pct(@initDuration, 99) as P99_Init_Duration'
```
5. Parse and flatten the result from the query call and save it in a
file.
6. Clean and destroy the deployed lambda resources upon completion,
cancellation, or failure.

**Testing**
Testing was done on a personal aws dev account with the exact IAM
permissions as the e2e testing aws account.
Example of a successful job:


https://github.com/liustve/aws-application-signals-test-framework/actions/runs/14389946356

Author: liustve

.github/workflows/dotnet-lambda-layer-perf-test.yml

@@ -0,0 +1,113 @@
+## Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+## SPDX-License-Identifier: Apache-2.0
+
+name: DotNet Lambda Layer Performance Test
+on:
+  workflow_dispatch:
+    inputs:
+      test_runs:
+        description: 'Number of test runs to perform'
+        required: true
+        default: 20
+        type: number
+        
+      dotnet-version:
+        description: 'dotnet version to use'
+        required: true
+        default: '8.0.x'
+        type: string  
+    
+jobs:
+  dotnet-lambda-layer-performance-test:
+    runs-on: ubuntu-latest 
+    permissions:
+        id-token: write
+        contents: read   
+
+    env:
+      NUM_TEST_RUNS: ${{ github.event.inputs.test_runs }}
+  
+    steps:
+    - name: Configure AWS Credentials
+      uses: aws-actions/configure-aws-credentials@v4
+      with:
+        role-to-assume: arn:aws:iam::${{ secrets.APPLICATION_SIGNALS_E2E_TEST_ACCOUNT_ID }}:role/${{ secrets.APPLICATION_SIGNALS_E2E_TEST_ROLE_NAME }}
+        aws-region: us-east-1     
+
+    - name: Checkout aws-otel-dotnet-instrumentation
+      uses: actions/checkout@v4
+      with:
+        repository: aws-observability/aws-otel-dotnet-instrumentation
+        path: aws-otel-dotnet-instrumentation
+
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: ${{ github.event.inputs.dotnet-version }}
+    
+    - name: Setup AWS Lambda Tools
+      run: dotnet tool install -g Amazon.Lambda.Tools
+
+    - name: Setup Terraform
+      uses: hashicorp/setup-terraform@v2
+
+    - name: Build and Deploy .NET Sample App and Lambda Layer
+      run: |
+        cd aws-otel-dotnet-instrumentation/sample-applications/lambda-test-apps/SimpleLambdaFunction/
+        ./build-and-deploy.sh
+
+    - name: Checkout current repository
+      uses: actions/checkout@v4
+      with:
+        path: current-repo
+    
+    - name: Run Cold Start Iterations for Base Lambda + Lambda Layer
+      run: |
+        cd current-repo
+        chmod +x lambda-layer-perf-test/lambda-layer-run.sh
+        ./lambda-layer-perf-test/lambda-layer-run.sh false SimpleLambdaFunction
+
+    - name: Remove Application Signals Lambda Layer
+      run: |
+          echo "Removing Lambda layer..."
+          
+          OUTPUT=$(aws lambda update-function-configuration \
+              --function-name SimpleLambdaFunction \
+              --layers [])
+  
+          echo "Lambda configuration:"
+          echo "$OUTPUT"
+  
+          LAYERS=$(echo "$OUTPUT" | jq -r '.Layers | length')
+  
+          if [ "$LAYERS" -ne 0 ]; then
+              echo "::error::Found $LAYERS layer(s) still attached to the function"
+              echo "::error::Layer details:"
+              echo "$OUTPUT" | jq -r '.Layers'
+              exit 1
+          else
+              echo "✅ Layers successfully removed"
+          fi
+ 
+    - name: Run Cold Start Iterations for Base Lambda
+      run: |
+        cd current-repo
+        chmod +x lambda-layer-perf-test/lambda-layer-run.sh
+        ./lambda-layer-perf-test/lambda-layer-run.sh true SimpleLambdaFunction
+
+    - name: Upload test results
+      uses: actions/upload-artifact@v4
+      with:
+        name: dotnet-performance-test-results
+        path: |
+            no_layer_results.txt
+            layer_results.txt
+        retention-days: 90
+
+    - name: Cleanup Terraform Resources
+      if: success() || failure() || cancelled()
+      run: |
+        cd aws-otel-dotnet-instrumentation/sample-applications/lambda-test-apps/SimpleLambdaFunction/terraform/lambda
+        echo "Starting Terraform cleanup..."
+        terraform init
+        terraform destroy -auto-approve

.github/workflows/node-lambda-layer-perf-test.yml

@@ -104,7 +104,7 @@ jobs:
     - name: Upload test results
       uses: actions/upload-artifact@v4
       with:
-        name: performance-test-results
+        name: js-performance-test-results
         path: |
             no_layer_results.txt
             layer_results.txt

.github/workflows/python-lambda-layer-perf-test.yml

@@ -95,7 +95,7 @@ jobs:
     - name: Upload test results
       uses: actions/upload-artifact@v4
       with:
-        name: performance-test-results
+        name: python-performance-test-results
         path: |
           no_layer_results.txt
           layer_results.txt