See #17798
const name = getDisplayNameForRoot(fiber);
    const counter = rootDisplayNameCounter.get(name) || 0;
    rootDisplayNameCounter.set(name, counter + 1);
    const pseudoKey = `${name}:${counter}`;
    rootPseudoKeys.set(id, pseudoKey);
  }
  function removeRootPseudoKey(id: number) {
    const pseudoKey = rootPseudoKeys.get(id);
    if (pseudoKey === undefined) {
      throw new Error('Expected root pseudo key to be known.');
    }
    const name = pseudoKey.substring(0, pseudoKey.lastIndexOf(':'));
    const counter = rootDisplayNameCounter.get(name);
    if (counter === undefined) {
      throw new Error('Expected counter to be known.');
    }
    if (counter > 1) {
      rootDisplayNameCounter.set(name, counter - 1);
    } else {
      rootDisplayNameCounter.delete(name);
    }
    rootPseudoKeys.delete(id);
  }