Channels and TPL Dataflow
Last Updated: February 1, 2026
Before Channels, .NET developers had several options for producer-consumer scenarios, none of which were ideal:
BlockingCollection<T> works but blocks threads. In an async world, blocking a thread to wait for data defeats the purpose of async/await.
ConcurrentQueue<T> is thread-safe but has no signaling mechanism. You need to poll or add your own synchronization, which is error-prone.
BufferBlock<T> from TPL Dataflow works but is part of a larger library designed for complex dataflow scenarios. Using the whole library just for a simple channel feels heavy.
Channels, introduced in .NET Core 2.1, fill this gap. They provide async-native producer-consumer communication with these properties:
- Async-first:
WriteAsyncandReadAsyncintegrate naturally with async/await - Bounded and unbounded options: Control memory usage with capacity limits
- High performance: Optimized for throughput with minimal allocations
- Clean API: Simple, focused design for the producer-consumer pattern
The diagram shows the evolution. BlockingCollection blocks threads, which is wasteful in async code where threads are precious. ConcurrentQueue requires you to implement signaling yourself (how does the consumer know an item arrived?). BufferBlock works but pulls in a larger library. Channels give you exactly what you need: async producer-consumer with minimal overhead.