g.writeFieldName(SRC_ID_FIELD_NAME);
g.writeNumber(e.getSourceId());
g.writeFieldName(OPCODE_FIELD_NAME);
g.writeString(e.getOpcode().toString());
g.writeFieldName("partId");
g.writeNumber(Integer.valueOf(e.getPartitionId()));
g.writeFieldName(VALUE_FIELD_NAME);
writer.write(datum, new JsonEncoder(schema, g));
g.writeEndObject();
g.writeEndObject();