private String getBlobIdLog() {
    return (blobId == null) ? "" : String.format(", BlobId: %s", blobId);
  }
Returns string to for logging {@code BlobId}, if the blob id if not {@code null}.
@return string to for logging {@code BlobId}. Returns empty string if the blob id is {@code null}.
ambry-router/src/main/java/com/github/ambry/router/SimpleOperationTracker.java