🔄 Async Streams in C#

🔄 Async Streams in C#

Async Streams were introduced in C# 8.0 to handle asynchronous sequences of data. They allow you to consume data as it becomes available, using IAsyncEnumerable<T> and await foreach.

📘 Example: Generating and Consuming Async Stream

  using System;
  using System.Collections.Generic;
  using System.Threading.Tasks;

  class Program {
      static async Task Main(string[] args) {
          await foreach (var number in GenerateNumbersAsync()) {
              Console.WriteLine($"Received: {number}");
          }
      }

      public static async IAsyncEnumerable<int> GenerateNumbersAsync() {
          for (int i = 0; i < 5; i++) {
              await Task.Delay(500); // Simulate async work
              yield return i;
          }
      }
  }
  

✅ Best Practices

• Use cancellation tokens to allow graceful termination of streams.
• Prefer ConfigureAwait(false) in library code to avoid deadlocks.
• Keep stream logic simple and predictable.
• Use try-catch blocks to handle exceptions inside async streams.
• Avoid blocking calls inside async stream methods.

📌 When to Use

• When consuming data from remote APIs or databases asynchronously.
• For real-time data feeds like telemetry or event logs.
• When processing large datasets without loading everything into memory.
• In UI applications where responsiveness is critical.

🚫 When Not to Use

• For small, synchronous datasets where async adds complexity.
• In performance-critical loops where await overhead is undesirable.
• When you need random access to data (use arrays or lists instead).

⚠️ Precautions

• Ensure exception handling is in place to avoid silent failures.
• Be aware of threading context—especially in UI apps.
• Don’t mix async streams with blocking code like .Result or .Wait().
• Use cancellation tokens to avoid memory leaks in long-running streams.

🎯 Advantages

• Efficiency: Processes data as it arrives, reducing memory usage.
• Responsiveness: Keeps UI and services responsive during long operations.
• Scalability: Ideal for streaming APIs and event-driven systems.
• Composability: Easily integrates with LINQ and other async methods.
• Modern syntax: Cleaner and more expressive than traditional async patterns.

📝 Conclusion

Async Streams are a powerful feature for handling asynchronous data flows in C#. They offer a clean, scalable, and memory-efficient way to process data over time. Use them when working with streaming sources, but be mindful of performance and cancellation.