public String getDateString() {
      return fields.get("WARC-Date");
    }
A 14-digit UTC timestamp formatted according to YYYY-MM-DDThh:mm:ssZ, described in the W3C
profile of ISO8601. The timestamp shall represent the instant that data capture for record
creation began. Multiple records written as part of a single capture event shall use the same
WARC-Date, even though the times of their writing will not be exactly synchronized.
@return The record's `WARC-Date` header field, as a string.
hbase-it/src/test/java/org/apache/hadoop/hbase/test/util/warc/WARCRecord.java