void setOperationException(RouterException exception) {
    RouterUtils.replaceOperationException(operationException, exception, this::getPrecedenceLevel);
  }
Set the exception associated with this operation.
If operationException exists, compare ErrorCodes of exception and existing operation Exception depending
on precedence level. An ErrorCode with a smaller precedence level overrides an ErrorCode with a larger precedence
level. Update the operationException if necessary.
@param exception the {@link RouterException} to possibly set.
ambry-router/src/main/java/com/github/ambry/router/TtlUpdateOperation.java