in timebase-kafka-connector/src/main/java/deltix/kafka/connect/RawMessageSerializer.java [111:116]
private Long getTimestamp(Struct value, String fieldName) {
Field timeField = value.schema().field(fieldName);
if (timeField == null)
throw new IllegalArgumentException("Schema has no time field " + fieldName);
return toInt64(value.get(timeField), timeField.schema());
}