message: Simplify concurrent request error handling
diff: @@ -56,22 +56,16 @@ async function limitConcurrency(fn) {
  });
  }
  - let result;
  - let error;
  -
  ongoingRequestCount++;
  try {
  - result = await fn();
  + return await fn();
  } catch (err) {
  - error = err;
  + // We explicitly do not handle the error here, but let it propogate.
  + throw err;
  } finally {
  ongoingRequestCount--;
  checkBacklog();
  }
  -
  - if (error) throw error;
  -
  - return result;
  }
  /**
  