get(runtime) {
		switch (this._mode) {
			case 0:
				return;
			case 1:
				return runtimeEqual(this._singleRuntime, runtime)
					? this._singleValue
					: undefined;
			default:
				return /** @type {RuntimeSpecMapInnerMap<R>} */ (this._map).get(
					getRuntimeKey(runtime)
				);
		}
	}
@param {RuntimeSpec} runtime the runtimes
@returns {R | undefined} value