Mpmc class

MPMC (Multiple-Producer Multiple-Consumer) channels - Maximum flexibility for complex patterns.

The most general channel type supporting concurrent producers AND consumers. Messages are distributed among consumers using competitive consumption - each message is received by exactly one consumer (no broadcasting).

Core Characteristics

  • Multiple producers: Thread-safe concurrent sending
  • Multiple consumers: Competitive message consumption (not broadcast)
  • FIFO ordering: Messages maintain send order across all consumers
  • Load balancing: Work automatically distributed among available consumers
  • Full cloning: Both senders and receivers can be cloned
  • Fair scheduling: Consumers compete fairly for messages

When to Use MPMC

  • Worker pools: Multiple producers ↔ multiple worker consumers
  • Load balancing: Distribute work across multiple processors
  • Pipeline stages: Multi-stage processing with multiple workers per stage
  • Distributed systems: Multiple clients ↔ multiple servers
  • Parallel processing: Fan-out work distribution patterns
  • Resource pools: Multiple requesters ↔ multiple resource providers

Important: Competitive Consumption

Unlike broadcast channels, each message goes to exactly one consumer. This enables load balancing but means consumers compete for messages.

Performance Considerations

  • Coordination overhead: Higher than MPSC due to consumer coordination
  • Good throughput: ~525-937ns per operation
  • Latest-only mode: Very fast for coalescing buffers
  • Memory efficiency: Shared buffer across all consumers

Example

{@tool snippet example/mpmc_example.dart} {@end-tool}

Constructors

Mpmc()

Properties

hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited

Static Methods

bounded<T>(int capacity, {String? metricsId}) → MpmcChannel<T>
channel<T>({int? capacity, DropPolicy policy = DropPolicy.block, OnDrop<T>? onDrop, bool chunked = true, String? metricsId}) → MpmcChannel<T>
latest<T>({String? metricsId}) → MpmcChannel<T>
unbounded<T>({bool chunked = true, String? metricsId}) → MpmcChannel<T>