isolated ThreadPoolExecutor for firmware update speed up (#11898)

hardware/opentrons_hardware/drivers/can_bus/driver.py

@@ -4,6 +4,7 @@
 import asyncio
 import platform
 from typing import Optional, Union, Dict, Any
+import concurrent.futures
 
 from can import Notifier, Bus, AsyncBufferedReader, Message
 
@@ -49,6 +50,7 @@ def __init__(self, bus: Bus, loop: asyncio.AbstractEventLoop) -> None:
  self._loop = loop
  self._reader = AsyncBufferedReader(loop=loop)
  self._notifier = Notifier(bus=self._bus, listeners=[self._reader], loop=loop)
+ self._executor = concurrent.futures.ThreadPoolExecutor(max_workers=5)
 
  @classmethod
  async def build(
@@ -113,7 +115,7 @@ async def send(self, message: CanMessage) -> None:
  is_fd=True,
  data=message.data,
  )
- await self._loop.run_in_executor(None, self._bus.send, m)
+ await self._loop.run_in_executor(self._executor, self._bus.send, m)
 
  async def read(self) -> CanMessage:
  """Read a message.