public static SpanAttachedEventTraceType valueOf(Integer code) {
        return CODE_DICTIONARY.get(code);
    }
The {@link SpanAttachedEventRecord} tracing context reference type.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/analysis/manual/spanattach/SpanAttachedEventTraceType.java