Explain magic number, var renaming

This extracts a constant and comments it for clarity. Also renames a
confusing waitgroup

kapacitor/kapa_client.go

@@ -6,7 +6,17 @@ import (
 	client "github.com/influxdata/kapacitor/client/v1"
 )
 
-const ListTaskWorkers = 4
+const (
+	// ListTaskWorkers describes the number of workers concurrently fetching
+	// tasks from Kapacitor. This constant was chosen after some benchmarking
+	// work and should likely work well for quad-core systems
+	ListTaskWorkers = 4
+
+	// TaskGatherers is the number of workers collating responses from
+	// ListTaskWorkers. There can only be one without additional synchronization
+	// around the output buffer from ListTasks
+	TaskGatherers = 1
+)
 
 // ensure PaginatingKapaClient is a KapaClient
 var _ KapaClient = &PaginatingKapaClient{}
@@ -43,18 +53,18 @@ func (p *PaginatingKapaClient) ListTasks(opts *client.ListTasksOptions) ([]clien
 		go p.fetchFromKapacitor(optChan, &wg, &once, taskChan, done)
 	}
 
-	var taskAsm sync.WaitGroup
-	taskAsm.Add(1)
+	var gatherWg sync.WaitGroup
+	gatherWg.Add(TaskGatherers)
 	go func() {
 		for task := range taskChan {
 			allTasks = append(allTasks, task...)
 		}
-		taskAsm.Done()
+		gatherWg.Done()
 	}()
 
 	wg.Wait()
 	close(taskChan)
-	taskAsm.Wait()
+	gatherWg.Wait()
 
 	return allTasks, nil
 }