Adding Concurrency in Pool Manager (#1698)

Concurrency in the pool manager allows specializing pods concurrently based on a specified limit. 

Co-authored-by: Vishal <vishal-biyani@users.noreply.github.com>

pkg/newcache/poolcache_test.go

@@ -0,0 +1,54 @@
+package poolcache
+
+import (
+	"log"
+	"testing"
+	"time"
+)
+
+func checkErr(err error) {
+	if err != nil {
+		log.Panicf("err: %v", err)
+	}
+}
+
+func TestPoolCache(t *testing.T) {
+	c := NewPoolCache()
+
+	c.SetValue("func", "ip", "value")
+
+	c.SetValue("func2", "ip2", "value2")
+
+	c.SetValue("func2", "ip22", "value22")
+
+	cc := c.ListValue()
+	if len(cc) != 3 {
+		log.Panicf("expected 2 items")
+	}
+	active := c.GetTotalAvailable("func2")
+	if active != 2 {
+		log.Panicf("expected 2 items")
+	}
+
+	c.DeleteValue("func2", "ip2")
+
+	c.MarkAvailable("func", "ip")
+
+	_, err := c.GetValue("func")
+	checkErr(err)
+
+	c.DeleteValue("func", "ip")
+
+	_, err = c.GetValue("func")
+	if err == nil {
+		log.Panicf("found deleted element")
+	}
+
+	c.SetValue("expires", "42", "all answers")
+
+	time.Sleep(150 * time.Millisecond)
+	_, err = c.GetValue("expires")
+	if err == nil {
+		log.Panicf("found expired element")
+	}
+}