Reapply "Merge branch 'main' of https://github.com/GooGuTeam/osu_lazer_api"

This reverts commit 68701dbb1d.

app/router/signalr/packet.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+from enum import IntEnum
+from typing import Any
+
+import msgpack
+from pydantic import BaseModel, model_validator
+
+SEP = b"\x1e"
+
+
+class PacketType(IntEnum):
+    INVOCATION = 1
+    STREAM_ITEM = 2
+    COMPLETION = 3
+    STREAM_INVOCATION = 4
+    CANCEL_INVOCATION = 5
+    PING = 6
+    CLOSE = 7
+
+class ResultKind(IntEnum):
+    ERROR = 1
+    VOID = 2
+    HAS_VALUE = 3
+
+
+def parse_packet(data: bytes) -> tuple[PacketType, list[Any]]:
+    length, offset = decode_varint(data)
+    message_data = data[offset : offset + length]
+    unpacked = msgpack.unpackb(message_data, raw=False)
+    return PacketType(unpacked[0]), unpacked[1:]
+
+
+def encode_varint(value: int) -> bytes:
+    result = []
+    while value >= 0x80:
+        result.append((value & 0x7F) | 0x80)
+        value >>= 7
+    result.append(value & 0x7F)
+    return bytes(result)
+
+
+def decode_varint(data: bytes, offset: int = 0) -> tuple[int, int]:
+    result = 0
+    shift = 0
+    pos = offset
+
+    while pos < len(data):
+        byte = data[pos]
+        result |= (byte & 0x7F) << shift
+        pos += 1
+        if (byte & 0x80) == 0:
+            break
+        shift += 7
+
+    return result, pos