Brett Profitt

Azure rejects PUT requests with content-length = 0, causing attempts to call Filesystem->write('key', '') to fail. This is especially problematic because InMemoryBuffer::open() attempts to write empty strings for certain modes.

Improve error message if handle() method not implemented in Command.

1

Small quality of life improvement that prevents an unhelpful error if you have a typo in the `handle()` method (and spent longer than you should have wondering what wasn't working)....

Read receipts for individual messages are available in https://github.com/bbernhard/signal-cli-rest-api/pull/534. This adds support via `Context.receipt("read")`.