code: static String getLazyKey(String key) {
      int start = startOfType(key);
      if (substringStartsWith(key, start, LAZY_PREFIX)) {
        return extractKey(key, start, key.substring(0, start), LAZY_PREFIX);
      } else {
        return null;
      }
    }
docs: Returns a key for the underlying binding of a Lazy<T> value. For example,
  if this is a key for a {@code Lazy<Foo>}, this returns the key for
  {@code Foo}. This retains annotations.