This is minor but it might be nice to fix the address sanitizer output that look like this:

runtime error: member access within misaligned address 0x000112e73f44 for type 'mu_Command', which requires 8 byte alignment

Thankfully this seems really to fix:

1. Add an expect(size % 8 == 0) at the top of mu_push_command
2. Add 4 bytes of padding to mu_RectCommand
3. Change mu_draw_text to do:

    int aligned_size = len + 8 - (len % 8);
    cmd = mu_push_command(ctx, MU_COMMAND_TEXT, sizeof(mu_TextCommand) + aligned_size);