anchor.diff:  
     # Set Environment Variables
     RUST_BACKTRACE = 1;
  +
  +  RUST_LOG = "calx-ecs=${log_level},vitral=${log_level},calx=${log_level},display=${log_level},world=${log_level},magog=${log_level}";
   }
  
positive.code: with import <nixpkgs> {};
  
  stdenv.mkDerivation {
    name = "rust-env";
    buildInputs = [
      rustup
  
negative.code:     }"
  
      rustup install stable
      rustup install nightly
      rustup default stable
      rustup update
  
  