in geronimo-microprofile-reporter/src/main/java/org/apache/geronimo/microprofile/reporter/storage/front/ReporterEndpoints.java [257:268]
public Html getSpans() {
final InMemoryDatabase<SpanEntry> db = database.getSpans();
return new Html("main.html")
.with("view", "spans.html")
.with("colors", COLORS)
.with("title", "Spans")
.with("spans", db == null ?
null :
db.snapshot().stream()
.map(it -> new Point<>(it.getTimestamp(), it.getValue()))
.collect(toList()));
}