feat: initial support for Extended Operations (#344)
Certain APIs with Long-Running Operations deviate from the semantics
in https://google.aip.dev/151 and instead define custom operation
messages, aka Extended Operations.
This change adds a PollingFuture subclass designed to be used with
Extended Operations. It is analogous and broadly similar to
google.api_core.operation.Operation and subclasses
google.api_core.future.polling.PollingFuture.
The full description of Extended Operation semantics is beyond the
scope of this change.
3 files changed
