RLViserRenderer crashes with panic in bytes.rs:151 during multi-process training

[alexx-ftw]

Description

When using RLViserRenderer from rlgym.rocket_league.rlviser during multi-process RL training on Windows, rlviser.exe crashes with a panic.

Error Message

thread '<unnamed>' panicked at src\bytes.rs:151:1:
called `Result::unwrap()` on an `Err` value: ()

Environment

• OS: Windows 11 64-bit
• Python: 3.11
• rlgym: latest from pip
• rlgym-learn: latest from pip

Code

from rlgym.rocket_league.rlviser import RLViserRenderer

renderer = RLViserRenderer()
env = RLGym(
    # ... other config
    renderer=renderer
)

Training Setup

• Multi-process training via LearningCoordinator (11 workers)
• 4v4 with random team sizes
• PPO algorithm

Steps to Reproduce

1. Create RLGym environment with RLViserRenderer
2. Start multi-process training with LearningCoordinator
3. Crash occurs during render() calls

The crash is in the rlviser binary's byte serialization code. Training works fine with renderer=None.

Stack Trace (RUST_BACKTRACE=full)

Binary doesn't have debug symbols:

   0:     0x7ff7d550a4dc - <unknown>
   1:     0x7ff7d4f501fb - <unknown>
   ...
  15:     0x7ff83247e8d7 - BaseThreadInitThunk
  16:     0x7ff83450c53c - RtlUserThreadStart