- Propagation of (rpc) method name.
- Invocation of the hook at (call, channel) x (creation, destruction)
- Added enum to identify the source of invocation.
- Fixed testing. Went from test fixture to simple test.
Allow plugins to extend the set of filters used by gRPC core:
- plugins at construction time can register against the 'channel_init' system to be allowed to mutate a new channel_stack_builder type
- channel_stack_builder provides a central and rather dynamic place to construct the list of filters required by a channel stack
- ultimately we construct the channel stack in the fashion we always have
This is also a prerequisite step to allowing filters to be implemented from wrapped languages.