Closing connections after calling return on AsyncIterator returned from watch

[kraenhansen]

What, How & Why?

This closes an issue, where calling return on the AsyncIterator returned by watch wouldn't free up the network connection.

The existing code was assuming that return would be called on the underlying iterator of a generator function, which is not explicit in the specification. The fix is to get a reference to the response body iterator and explicitly call return on this, while deferring all other implementation to a renamed watchImpl method.

The syntax involved in unwrapping and rewrapping the iterator is a bit involved, since watch must return synchronously while the response body iterator is obtained through a promise.

☑️ ToDos

• 📝 Changelog entry
• 📝 Compatibility label is updated or copied from previous entry
• 🚦 Tests (manually, locally)
• 🔀 Executed flexible sync tests locally if modifying flexible sync
• 📦 Updated internal package version in consuming package.jsons (if updating internal packages)
• 📱 Check the React Native/other sample apps work if necessary
• 📝 Public documentation PR created or is not necessary
• 💥 Breaking label has been applied or is not necessary

[fronck]

I that console.log was left in there by accident :)

[fronck]

LGTM 👍

[kneth]

👍 😮