registerStampAlternative(c, when, stamp) {
    const alternatives = this.#map.get(c) ?? [];
    alternatives.push([when, stamp]);
    this.#map.set(c, alternatives);
    return this;
  }
Register a possible Stamp for subset of possible properties for the given Component
@param c Component
@param when Property filter for when the Stamp applies
@param stamp Stamp to register
@returns this (for chaining)