public byte[] getFilterString() {
    setFilterString(org.apache.thrift.TBaseHelper.rightSize(filterString));
    return filterString == null ? null : filterString.array();
  }
Returns true if field timeRange is set (has been assigned a value) and false otherwise
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/generated/TScan.java