Add TCP performance monitoring with HTTP/2 support

- Enhanced HTTP2Downloader and HTTP2Uploader classes with detailed timing analysis
- Added --monitor-tcp flag for enabling TCP performance monitoring
- Implemented pause detection and fastest period identification
- Added comprehensive TCP Performance Analysis report
- Respects --bytes flag for consistent unit display (Mbit/s or MB/s)
- Automatic HTTP/2 enablement when TCP monitoring is requested
- Real-time connection event tracking and timing data collection

tcp_monitoring_demo.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+"""
+TCP Monitoring Demo for speedtest-cli
+
+This script demonstrates the new TCP monitoring capabilities added to speedtest-cli.
+It shows how to use the --monitor-tcp flag to get detailed performance analysis.
+"""
+
+import subprocess
+import sys
+import time
+
+def run_speedtest_with_monitoring():
+    """Run speedtest with TCP monitoring enabled"""
+    print("=== Speedtest-cli TCP Monitoring Demo ===")
+    print()
+    print("This demo shows the new TCP monitoring capabilities that help identify:")
+    print("- Fastest periods during speed tests")
+    print("- Pauses and timeouts in data transfer")
+    print("- Detailed timing analysis for HTTP/2 connections")
+    print()
+    
+    # Check if httpx is available
+    try:
+        import httpx
+        print("✓ httpx is available - HTTP/2 support enabled")
+    except ImportError:
+        print("✗ httpx not available - HTTP/2 monitoring requires httpx")
+        print("  Install with: pip install httpx")
+        return
+    
+    print()
+    print("Running speedtest with TCP monitoring...")
+    print("=" * 50)
+    
+    # Run speedtest with monitoring
+    cmd = [sys.executable, 'speedtest.py', '--http2', '--monitor-tcp', '--simple']
+    
+    try:
+        result = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
+        
+        if result.returncode == 0:
+            print(result.stdout)
+            if result.stderr:
+                print("Debug output:")
+                print(result.stderr)
+        else:
+            print(f"Error running speedtest: {result.stderr}")
+            
+    except subprocess.TimeoutExpired:
+        print("Speedtest timed out after 2 minutes")
+    except Exception as e:
+        print(f"Error: {e}")
+
+def show_usage_examples():
+    """Show usage examples for the new TCP monitoring feature"""
+    print("\n=== Usage Examples ===")
+    print()
+    print("Basic TCP monitoring:")
+    print("  ./speedtest.py --http2 --monitor-tcp")
+    print()
+    print("TCP monitoring with debug output:")
+    print("  ./speedtest.py --http2 --monitor-tcp --debug")
+    print()
+    print("TCP monitoring with simple output:")
+    print("  ./speedtest.py --http2 --monitor-tcp --simple")
+    print()
+    print("Note: --monitor-tcp automatically enables --http2 if not already specified")
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1 and sys.argv[1] == "--help":
+        show_usage_examples()
+    else:
+        run_speedtest_with_monitoring()
+        show_usage_examples()