function getEccLib() {
  if (!_ECCLIB_CACHE.eccLib)
    throw new Error(
      'No ECC Library provided. You must call initEccLib() with a valid TinySecp256k1Interface instance',
    );
  return _ECCLIB_CACHE.eccLib;
}
Retrieves the ECC Library instance.
Throws an error if the ECC Library is not provided.
You must call initEccLib() with a valid TinySecp256k1Interface instance before calling this function.
@returns The ECC Library instance.
@throws Error if the ECC Library is not provided.