perf: query data AS OF SYSTEM TIME (#5231)

Queries the data in the storage layser at the timestamp when the call hit the API layer

internal/api/call/duration.go

@@ -0,0 +1,38 @@
+package call
+
+import (
+	"context"
+	"time"
+)
+
+type durationKey struct{}
+
+var key *durationKey = (*durationKey)(nil)
+
+// WithTimestamp sets [time.Now()] adds the call field to the context
+// if it's not already set
+func WithTimestamp(parent context.Context) context.Context {
+	if parent.Value(key) != nil {
+		return parent
+	}
+	return context.WithValue(parent, key, time.Now())
+}
+
+// FromContext returns the [time.Time] the call hit the api
+func FromContext(ctx context.Context) (t time.Time) {
+	value := ctx.Value(key)
+	if t, ok := value.(time.Time); ok {
+		return t
+	}
+
+	return t
+}
+
+// Took returns the time the call took so far
+func Took(ctx context.Context) time.Duration {
+	start := FromContext(ctx)
+	if start.IsZero() {
+		return 0
+	}
+	return time.Since(start)
+}