handle uninitialized state

Makefile

@@ -9,13 +9,13 @@ fmt: $(sources)
 	go fmt
 
 check: $(sources)
-	go test -count 1
+	go test -v -count 1
 
 race: $(source)
-	go test -count 1 -race
+	go test -v -count 1 -race
 
 .cover: $(sources)
-	go test -count 1 -coverprofile .cover
+	go test -v -count 1 -coverprofile .cover
 
 cover: .cover
 	go tool cover -func .cover

lib.go

@@ -158,10 +158,13 @@ type Pool[R any] struct {
 	pool pool[R]
 }
 
-// ErrNoItems is returned on Get calls when the pool does not enough items and it was initialized without an
+// ErrNoItems is returned on Get calls when the pool does not have enough items and it was initialized without an
 // allocate function.
 var ErrNoItems = errors.New("not enough items in the pool")
 
+// ErrUninitialized is returned when the pool was not initialized.
+var ErrUninitialized = errors.New("pool uninitialized")
+
 // String returns the string representation of the EventType binary flag, including all the flags that are set.
 func (et EventType) String() string {
 	var s []string
@@ -283,6 +286,10 @@ func Make[R any](alloc func() (R, error), free func(R), o Options) Pool[R] {
 // function returns an error, it returns the available items and that error. If events were configured, GetN
 // triggers a GetOperation event.
 func (p Pool[R]) GetN(n int) ([]R, error) {
+	if p.pool.state == nil {
+		return nil, ErrUninitialized
+	}
+
 	return p.pool.get(n)
 }
 
@@ -290,6 +297,11 @@ func (p Pool[R]) GetN(n int) ([]R, error) {
 // ErrEmpty. If the pool is empty, and the allocation function returns an error, it returns that error. If
 // events were configured, Get triggers a GetOperation event.
 func (p Pool[R]) Get() (R, error) {
+	if p.pool.state == nil {
+		var r R
+		return r, ErrUninitialized
+	}
+
 	r, err := p.pool.get(1)
 	if err != nil {
 		var rr R
@@ -306,6 +318,10 @@ func (p Pool[R]) Get() (R, error) {
 // sudden drop in the number of active items. If the pool needs to be prewarmed, or prepared for an expected
 // spike of traffic, consider using the Load method.
 func (p Pool[R]) Put(i ...R) {
+	if p.pool.state == nil {
+		return
+	}
+
 	p.pool.put(i...)
 }
 
@@ -315,11 +331,19 @@ func (p Pool[R]) Put(i ...R) {
 // shrinking algorithm, it may work more consistently, if the algorithm is notified about the change in the
 // active items. The other purpose is to allow the pool to reflect these cases in the events and the stats.
 func (p Pool[R]) DropN(n int) {
+	if p.pool.state == nil {
+		return
+	}
+
 	p.pool.drop(n)
 }
 
 // Drop is like DropN, but for a single item.
 func (p Pool[R]) Drop() {
+	if p.pool.state == nil {
+		return
+	}
+
 	p.pool.drop(1)
 }
 
@@ -327,17 +351,29 @@ func (p Pool[R]) Drop() {
 // It can be useful in scenarios where prewarming or preparing for a sudden traffic spike is necessary. If
 // events were configured, it triggers a LoadOperation event.
 func (p Pool[R]) Load(i []R) {
+	if p.pool.state == nil {
+		return
+	}
+
 	p.pool.load(i)
 }
 
 // Stats returns statistics about the current state of the pool. It contains the current number of active/idle
 // items, and perpetual counters for the various pool operations.
 func (p Pool[R]) Stats() Stats {
+	if p.pool.state == nil {
+		return Stats{}
+	}
+
 	return p.pool.stats()
 }
 
 // Free releases all idle items in the pool. While the pool stays operational, Free is meant to be used when the
 // pool is not required anymore.
 func (p Pool[R]) Free() {
+	if p.pool.state == nil {
+		return
+	}
+
 	p.pool.freePool()
 }