Print numeric tags when printing the trace (#179)

* Print numeric tags when printing the trace

internal/driver/driver_test.go

 		{"tags", "heap"},
 		{"tags,unit=bytes", "heap"},
 		{"traces", "cpu"},
+		{"traces", "heap_tags"},
 		{"dot,alloc_space,flat,focus=[234]00", "heap_alloc"},
 		{"dot,alloc_space,flat,tagshow=[2]00", "heap_alloc"},
 		{"dot,alloc_space,flat,hide=line.*1?23?", "heap_alloc"},
 		for _, s := range p.Sample {
 			s.NumLabel["bytes"] = append(s.NumLabel["bytes"], tags...)
 		}
+	case "heap_tags":
+		p = heapProfile()
+
+		for i := 0; i < len(p.Sample); i += 2 {
+			s := p.Sample[i]
+			if s.Label == nil {
+				s.Label = make(map[string][]string)
+			}
+			s.NumLabel["request"] = s.NumLabel["bytes"]
+			s.Label["key1"] = []string{"tag"}
+		}
 
 	case "contention":
 		p = contentionProfile()

internal/driver/testdata/pprof.heap_tags.traces

+Build ID: buildid
+comment
+Type: inuse_space
+-----------+-------------------------------------------------------
+      key1:  tag
+     bytes:  102400
+   request:  102400
+    1000kB   line1000
+             line2001
+             line2000
+             line3002
+             line3001
+             line3000
+-----------+-------------------------------------------------------
+     bytes:  204800
+    3.91MB   line1000
+             line3001
+             line3000
+-----------+-------------------------------------------------------
+      key1:  tag
+     bytes:  1638400
+   request:  1638400
+   62.50MB   line2001
+             line2000
+             line3002
+             line3000
+-----------+-------------------------------------------------------
+     bytes:  409600
+   31.25MB   line3002
+             line3001
+             line3000
+-----------+-------------------------------------------------------

internal/report/report.go

 		}
 		sort.Strings(labels)
 		fmt.Fprint(w, strings.Join(labels, ""))
+
+		// Print any numeric labels for the sample
+		var numLabels []string
+		for k, v := range sample.NumLabel {
+			numLabels = append(numLabels, fmt.Sprintf("%10s:  %s\n", k, strings.Trim(fmt.Sprintf("%d", v), "[]")))
+		}
+		sort.Strings(numLabels)
+		fmt.Fprint(w, strings.Join(numLabels, ""))
+
 		var d, v int64
 		v = o.SampleValue(sample.Value)
 		if o.SampleMeanDivisor != nil {