Fix unchecked error returns in example files

- Add proper error handling for all defer cache.Close() calls
- Use anonymous functions to check Close() errors and log them
- This resolves golangci-lint errcheck warnings in:
  - examples/redis-cache/main.go
  - examples/metrics/main.go
  - examples/compression/main.go
  - examples/debug/main.go
  - examples/gin-web-server/main.go
  - examples/echo-web-server/main.go
  - examples/batch-processing/main.go

Author: vnykmshr

examples/batch-processing/main.go

@@ -472,7 +472,11 @@ func main() {
 	if err != nil {
 		log.Fatalf("Failed to create processor: %v", err)
 	}
-	defer processor.Close()
+	defer func() {
+		if err := processor.Close(); err != nil {
+			log.Printf("Error closing processor: %v", err)
+		}
+	}()
 
 	// Warm up cache
 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)

examples/compression/main.go

@@ -100,7 +100,11 @@ func noCompressionExample() {
 	if err != nil {
 		log.Fatalf("Failed to create cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Store some large data
 	largeData := generateLargeJSON()
@@ -135,7 +139,11 @@ func gzipCompressionExample() {
 	if err != nil {
 		log.Fatalf("Failed to create cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Store some large data
 	largeData := generateLargeJSON()
@@ -195,7 +203,11 @@ func deflateCompressionExample() {
 	if err != nil {
 		log.Fatalf("Failed to create cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Test with very large repetitive data that should compress well
 	repeatedText := strings.Repeat("This is a test string that repeats many times to demonstrate compression efficiency. ", 1000)

examples/debug/main.go

@@ -19,7 +19,11 @@ func main() {
 	if err != nil {
 		log.Fatalf("Failed to create cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Populate cache with some data
 	fmt.Println("Populating cache with test data...")

examples/echo-web-server/main.go

@@ -455,7 +455,11 @@ func (s *APIServer) healthCheck(c echo.Context) error {
 }
 
 func (s *APIServer) Start(address string) error {
-	defer s.cacheManager.Close()
+	defer func() {
+		if err := s.cacheManager.Close(); err != nil {
+			log.Printf("Error closing cache manager: %v", err)
+		}
+	}()
 	return s.echo.Start(address)
 }
 

examples/gin-web-server/main.go

@@ -265,7 +265,11 @@ func (s *WebServer) healthCheck(c *gin.Context) {
 }
 
 func (s *WebServer) Run(addr string) error {
-	defer s.userService.Close()
+	defer func() {
+		if err := s.userService.Close(); err != nil {
+			log.Printf("Error closing user service: %v", err)
+		}
+	}()
 	return s.router.Run(addr)
 }
 

examples/metrics/main.go

@@ -95,7 +95,11 @@ func prometheusExample() {
 	if err != nil {
 		log.Fatalf("Failed to create cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Wrap function with caching
 	cachedFetchUser := obcache.Wrap(cache, fetchUserData)
@@ -173,7 +177,11 @@ func opentelemetryExample() {
 	if err != nil {
 		log.Fatalf("Failed to create cache with OTel metrics: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Simulate cache operations
 	fmt.Println("📊 Generating cache activity for OpenTelemetry metrics...")
@@ -247,7 +255,11 @@ func multiExporterExample() {
 	if err != nil {
 		log.Fatalf("Failed to create multi-metrics cache: %v", err)
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	fmt.Println("📊 Generating activity for multiple exporters...")
 

examples/redis-cache/main.go

@@ -63,7 +63,11 @@ func basicRedisExample() {
 		fmt.Println("⚠️  Make sure Redis is running on localhost:6379")
 		return
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Store a user in cache
 	user := &User{ID: 1, Name: "Alice", Email: "alice@example.com"}
@@ -100,7 +104,11 @@ func functionWrappingExample() {
 		fmt.Println("⚠️  Make sure Redis is running on localhost:6379")
 		return
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Wrap the expensive function with caching
 	cachedGetUser := obcache.Wrap(cache, getUserFromDatabase,
@@ -165,7 +173,11 @@ func distributedCachingExample() {
 		log.Printf("Failed to create distributed cache: %v", err)
 		return
 	}
-	defer cache.Close()
+	defer func() {
+		if err := cache.Close(); err != nil {
+			log.Printf("Error closing cache: %v", err)
+		}
+	}()
 
 	// Simulate distributed caching scenario
 	fmt.Println("🌐 Simulating distributed caching...")