EV3: Fix flashing on Windows.

Windows requires a reportid byte at the front of each sent
message for an HID device, even if the device doesn't use
reportids. Adding this synthetic 0x00 to the front of the
message enables successful EV3 flashing on Windows.

Author: jaguilar

pybricksdev/connections/ev3.py

@@ -4,6 +4,7 @@
 import asyncio
 import enum
 import itertools
+import platform
 import struct
 from typing import Callable
 
@@ -97,6 +98,14 @@ def _send_command(self, command: Command, payload: bytes | None = None) -> int:
         if payload is not None:
             message += payload
 
+        if platform.system() == "Windows":
+            # On Windows, HID reports require an extra leading byte for the
+            # report ID, even if it's zero. Note that although Windows would
+            # add a synthetic 0x00 HID byte to the front of reads as well,
+            # we don't have to handle it because hidapi.dll strips that byte
+            # in hid_read().
+            message = b'\x00' + message
+
         self._device.write(message)
 
         return message_number