Beware of double hash indexing like this. If it it ever happens that `GOLIATH_HEADERS` are missing, you'll get that infernal `NoMethodError: undefined method '[]' for nil:NilClass` exception. We prefer 2 lines for that reason
```ruby
goliath_headers = env[GOLIATH_HEADERS] or raise "Didn't find GOLIATH_HEADERS in #{env.inspect}"
goliath_headers[WS_KEY] or raise "Didn't find WS_KEY in #{goliath_headers.inspect}"
```
Note that when a key isn't found, the above pattern shows you just what you need to know about what _was_ there.  Also note the above won't return `nil` to your callers if `WS_KEY` is missing.  I didn't look but chances are the caller(s) aren't coded to handle `nil`.