default String resolveStartpointToOffset(SystemStreamPartition systemStreamPartition, Startpoint startpoint) {
    throw new UnsupportedOperationException();
  }
Resolves the startpoint to a system specific offset.
@param startpoint represents the startpoint.
@param systemStreamPartition represents the system stream partition.
@return the resolved offset.
samza-api/src/main/java/org/apache/samza/system/SystemAdmin.java