private static Operation valueFrom(final Scan scan) {
    if (scan == null) {
      return null;
    }
    return Operation.SCAN;
  }
Construct {@link Span} instances originating from "table operations" -- the verbs in our public
API that interact with data in tables.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/trace/TableOperationSpanBuilder.java