This lets debug tools list the types that clients are wielding, so
that they can build a dataflow graph and other debugging views.
Updates #15160
Signed-off-by: David Anderson <dave@tailscale.com>
Enables monitoring events as they flow, listing bus clients, and
snapshotting internal queues to troubleshoot stalls.
Updates #15160
Signed-off-by: David Anderson <dave@tailscale.com>
Publicly exposed debugging functions will use these hooks to
observe dataflow in the bus.
Updates #15160
Signed-off-by: David Anderson <dave@tailscale.com>
