How to use the @aws-cdk/cx-api.ASSET_PREFIX_SEPARATOR function in @aws-cdk/cx-api

contentType
  });

  const relativePath = path.relative(process.cwd(), asset.path);

  const s3url = `s3://${toolkitInfo.bucketName}/${key}`;
  debug(`S3 url for ${relativePath}: ${s3url}`);
  if (changed) {
    success(`Updated: ${colors.bold(relativePath)} (${asset.packaging})`);
  } else {
    debug(`Up-to-date: ${colors.bold(relativePath)} (${asset.packaging})`);
  }

  return [
    { ParameterKey: asset.s3BucketParameter, ParameterValue: toolkitInfo.bucketName },
    { ParameterKey: asset.s3KeyParameter, ParameterValue: `${s3KeyPrefix}${cxapi.ASSET_PREFIX_SEPARATOR}${filename}` },
    { ParameterKey: asset.artifactHashParameter, ParameterValue: hash },
  ];
}