public short getAccountId() {
    return accountId;
  }
Gets the id of the {@link Account} who created this blob. If this information was not available when the
blobId was formed, it will return {@link Account#UNKNOWN_ACCOUNT_ID}.
@return The id of the {@link Account} who created this blob.
ambry-commons/src/main/java/com/github/ambry/commons/BlobId.java