Streamr Client 5.0.0

[timoxley]

This is basically a new streamr client with rebuilt internals, including a message subscription “pipeline”, more robust/understandable/consistent connection handling and a lot more tests + reliability around connection & timing issues.

External interface is largely the same, but timings may differ and there may be some edge cases not covered by tests.

This is built on top of, and supersedes changes in #156, #160, #162, #164 & #166

Rough WIP Changelog

• subscribe/resend methods are now async.
• No more subscribed event (subscribe() promise now resolves when this would have fired)
• No more no_resend event, only resent whether there were messages or not.
• Subscribe, resend & subscribe with resend all use the same machinery, so their behaviour should be identical.
• Added collect() function to subscriptions that collects the results into an array of messages and resolves when the subscription ends, mainly/only useful for resends.
• Subscriptions are async iterators. You can access this interface if you don’t supply an onMessage handler to subscribe/resend.
• Connection emits done when it's been disconnected and will not reconnect.
• Connection emits connected only when it's connected and will not be immediately disconnecting.
• autoConnect + autoDisconnect options become forcibly disabled if you explicitly call connect() or disconnect(). This is because I could not come up a sensible, consistent expected behaviour that combined explicit & automatic connect/disconnect. Can reenable auto behaviour without creating a new client or mutating options using enableAutoConnect()/enableAutoDisconnect(). This means if you connect you must disconnect or enableAutoDisconnect() to close the connection.
• connect() & disconnect() no longer error if already {dis}connecting/{dis}connected. This is basically what ensureConnected/ensureDisconnected provided before.
• The ensureConnected/ensureDisconnected methods still exist but are now just aliases of connect & disconnect.
• Uses latest version of streamr protocol 7.0.0 to get these fixes + more: Handle multiple gaps streamr-client-protocol-js#46 & Don't break if explicitly marking messages out of order. streamr-client-protocol-js#47
• Random errors no longer disconnect the client.
• Reconnecting on unexpected disconnection should work reliably now, there's a hard distinction between user-initiated disconnects and those that happen by accident.
• Resends should work more reliably now.
• Cleaned up and improved logging. Is more verbose but should be clearer what’s going on. todo: move logging to pino
• Removed regenerator babel transform.
• source-maps are now always on.
• New BundleAnalyzerPlugin produces a bundle size report in dist/report.html. This is downloadable as an artifact in CI builds
• Almost all functionality is now tested via integration tests, rather than implementation-coupled+heavily mocked unit tests.
• Updated all tests to not use async (done) => in preparation for jest-circus jest runner being enabled by default in Jest 27+. Enabled jest-circus by default anyway. This fixes an issue where if a test fails asynchronously, the afterEach/afterAll hooks would run unchained i.e. beforeEach for next test would start before afterEach was complete. This led to some very confusing test results at times.
• Moved data union tests into “flakey” test folder. These tests still run, but won’t fail CI.
• Integrated new DU-2 changes
• Significant improvements to CI workflow

Related: #NET-159