csharp-async

by github

Best practices guide for C# asynchronous programming patterns and pitfalls. Covers naming conventions (Async suffix), return types (Task, ValueTask, avoid void), and exception handling strategies including ConfigureAwait and Task.FromException Highlights performance optimization techniques: Task.WhenAll for parallel execution, Task.WhenAny for timeouts, and cancellation token usage Documents critical pitfalls to avoid: blocking calls like .Wait() and .Result, async void methods outside event... npx skills add https://github.com/github/awesome-copilot --skill csharp-async Download ZIPGitHub36.2k

C# Async Programming Best Practices

Your goal is to help me follow best practices for asynchronous programming in C#.

Naming Conventions

• Use the 'Async' suffix for all async methods

• Match method names with their synchronous counterparts when applicable (e.g., GetDataAsync() for GetData())

Return Types

• Return Task<T> when the method returns a value

• Return Task when the method doesn't return a value

• Consider ValueTask<T> for high-performance scenarios to reduce allocations

• Avoid returning void for async methods except for event handlers

Exception Handling

• Use try/catch blocks around await expressions

• Avoid swallowing exceptions in async methods

• Use ConfigureAwait(false) when appropriate to prevent deadlocks in library code

• Propagate exceptions with Task.FromException() instead of throwing in async Task returning methods

Performance

• Use Task.WhenAll() for parallel execution of multiple tasks

• Use Task.WhenAny() for implementing timeouts or taking the first completed task

• Avoid unnecessary async/await when simply passing through task results

• Consider cancellation tokens for long-running operations

Common Pitfalls

• Never use .Wait(), .Result, or .GetAwaiter().GetResult() in async code

• Avoid mixing blocking and async code

• Don't create async void methods (except for event handlers)

• Always await Task-returning methods

Implementation Patterns

• Implement the async command pattern for long-running operations

• Use async streams (IAsyncEnumerable ) for processing sequences asynchronously

• Consider the task-based asynchronous pattern (TAP) for public APIs

When reviewing my C# code, identify these issues and suggest improvements that follow these best practices.