`samplerd` service

[goodboy]

Adds a new singleton samplerd actor to our service tree which provides:

• single process sample incrementing for all registered ShmArray buffers thereby providing a unified and synchronized "step update" for all real-time flows.
• single process-task for all index-step broadcasting ensuring all consumers are seeing the same update msgs in tandem.

The overall service tree should now look something like:

pikerd /home/goodboy/.virtualenvs/piker310/bin/pikerd --tsdb --pdb
  ├─python3 -m tractor._child --uid ('marketstored', '60ab7cd9-819e-4fb8-95ce-ea343ef1aa81') --parent_addr('12
  │   └─3*[{python3}]
  ├─python3 -m tractor._child --uid ('brokerd.binance', '12de17a0-5e63-4083-879d-45772647dd68') --parent_addr(
  │   └─3*[{python3}]
  ├─python3 -m tractor._child --uid ('brokerd.ib', 'ec8fb1bc-8dd0-4317-8bd3-f615a6d7c255') --parent_addr('127.
  │   └─4*[{python3}]
  ├─python3 -m tractor._child --uid ('samplerd', '42107775-c146-4589-8aaa-7aa170faa618') --parent_addr('127.0.
  │   └─3*[{python3}]
  ├─python3 -m tractor._child --uid ('emsd', 'ecd5fdbc-aa05-404a-b738-31056b9c24dd') --parent_addr('127.0.0.1'
  │   ├─python3 -m tractor._child --uid ('paperboi.binance', '6b8833a2-6c20-494c-8de8-ff6b9d1015eb') --parent_addr
  │   │   └─3*[{python3}]
  │   └─3*[{python3}]
  └─3*[{pikerd}]

---

Further included enhancements in this patchset:

• simplified ._daemon.Services API which presents as a singleton class with @classmethods and is expected to exist once-and-only-once in the pikerd actor.
• improved quote feed throttling by framing ticks by type over a given throttle period resulting in lower transmission rates and a "update from last" msg format which greatly speeds up the graphics update loop.
  • now accomplished by a self-contained framing helper func
• misc fixes for history loading from the tsdb mostly to do with explicit query error logging and a guard to avoid inf looping on duplicate history frame detection. .
• syncing FSP flows with their sources by copying epoch time indexing from src to dst.
• misc broker backend fixes:
  • kraken fix to avoid ws unsubs on reconnect and adjustment to better parse src_fiat for position tracking.
  • binance always query for an extra 1Min ohlc bar to ensure latest sample step is being used.

---

What we might factor out:

• [x] fix to avoid cancelling the dark clearing loop on data feed Laggeds => moved into #441 which requires https://github.com/goodboy/tractor/pull/343 from tractor

---

Further TODOs:

• [x] add some basic service tree tests
  • [x] verify a samplerd is always spawned
  • [x] verify an fsp cluster can be spawned and queried
  • [x] verify an emsd and paperboi can be allocated and queried

[goodboy]

Just reproed this failure from CI after doing an update to all packages.

Not sure if it's tractor dev pinning or something else..

[goodboy]

Test suite in fe4fb37 peepers!

This is ready to land after review 🏄🏼

[goodboy]

Bleh/lol that test is failing do to error msg differences in dev branch of tractor vs. this..

[goodboy]

There, now tractor's branch piker_pin is in the right spot 🏄🏼