issue: #38399
- add metrics for broadcaster component.
- add metrics for wal flusher component.
- add metrics for wal interceptors.
- add slow log for wal.
- add more label for some wal metrics. (local or remote/catcup or
tailing...)
Signed-off-by: chyezh <chyezh@outlook.com>
issue: #33285
- move streaming related proto into pkg.
- add v2 message type and change flush message into v2 message.
Signed-off-by: chyezh <chyezh@outlook.com>
issue: #33285
- add two grpc resolver (by session and by streaming coord assignment
service)
- add one grpc balancer (by serverID and roundrobin)
- add lazy conn to avoid block by first service discovery
- add some utility function for streaming service
Signed-off-by: chyezh <chyezh@outlook.com>
