send abstract method

void send(
  1. Object? message

Sends an asynchronous message through this send port, to its corresponding ReceivePort.

If the sending and receiving isolates do not share the same code (an isolate created using Isolate.spawnUri does not share the code of the isolate that spawned it), the transitive object graph of message can only contain the following kinds of objects:

If the sender and receiver isolate share the same code (e.g. isolates created via Isolate.spawn), the transitive object graph of message can contain any object, with the following exceptions:

Instances of classes that either themselves are marked with @pragma('vm:isolate-unsendable'), extend or implement such classes cannot be sent through the ports.

Apart from those exceptions any object can be sent. Objects that are identified as immutable (e.g. strings) will be shared whereas all other objects will be copied.

The send happens immediately and may have a linear time cost to copy the transitive object graph. The send itself doesn't block (i.e. doesn't wait until the receiver has received the message). The corresponding receive port can receive the message as soon as its isolate's event loop is ready to deliver it, independently of what the sending isolate is doing.

Note: Due to an implementation choice the Dart VM made for how closures represent captured state, closures can currently capture more state than they need, which can cause the transitive closure to be larger than needed. Open bug to address this:


void send(Object? message);