in flume-elasticsearch-sink/src/main/java/org/apache/flume/sink/elasticsearch/ContentBuilderUtil.java [40:48]
public static void appendField(XContentBuilder builder, String field,
byte[] data) throws IOException {
XContentType contentType = XContentFactory.xContentType(data);
if (contentType == null) {
addSimpleField(builder, field, data);
} else {
addComplexField(builder, field, contentType, data);
}
}