spawn 0.1.0

Background execution for Dart that works everywhere - isolates on native, Web Workers on the web, one API. The missing web half of dart:isolate.

Changelog

0.1.0

First release.

• spawn(entry) starts a worker on an isolate (native) or a compiled Web Worker payload (web) behind one API, and completes only once the handler is running.
• Worker / WorkerClient: post, request, a broadcast events stream buffered until its first listener, graceful and forced close, and attach() for additional clients of one worker.
• WorkerChannel: messages, send, handleRequests, initialMessage, onClose.
• One portability contract on every platform — the portable set, or WireMessage — so a message that works on the VM works in a browser.
• A documented 12-byte wire envelope with a WireRegistry, and SpawnEntry.protocol to register a protocol's decoders on both ends.
• transfer: lists: a real move on the web, and a skipped copy on native for byte payloads. SpawnCaps.zeroCopyTransfer reports which you got.
• SpawnService lifetimes with pluggable, reference-counted ServiceProviders and an error at spawn time that names the missing registration.
• spawnLocal runs a handler in process behind a real Worker, for tests and as the web debug fallback when a payload has not been built.
• dart run spawn:build compiles lib/workers/*.dart to web payloads, with content-hash skipping. No code generation and no build_runner.
• JobEntry parses and validates; Jobs.enqueue throws until deferred, OS-scheduled work lands.
• SpawnEntry.native is reserved for a C- or wasm-hosted worker and throws.
• PlatformValue carries an opaque platform object - a VideoFrame, AudioData, ImageBitmap, OffscreenCanvas - through a channel untouched. It always transfers rather than clones, including from a request response, because most of those types cannot be cloned at all. This is what lets a decode worker hand finished frames to the main thread.
• spawn:build skips files in the worker directory that declare no main, so a worker can sit next to its conditional-import stubs and helpers, and its up-to-date check now covers path dependencies. A payload that ignored changes to a sibling package under active development is worse than no caching at all: the tests pass against code that is no longer there.