prevent memprof file overwrites for small intervals

Previously, the timestamp was accurate only down to seconds. For smaller intervals,
this would truncate the previous file(s). Now, for small intervals, the number of
microseconds is appended to the file name.

Added the possibility to disable timestamps in the memory profile file names and use
increments of 1 instead.

Updated the memory profiling integration tests.

cores/core.go

@@ -136,7 +136,14 @@ type MemoryProfilingParams struct {
 	DirPath  string        // directory path where memory profiles will be saved
 	Interval time.Duration // duration between consecutive memory profile captures
 	MaxFiles int           // maximum number of profile files to retain
-	APIOpts  map[string]any
+
+	// UseTimestamp determines if the filename includes a timestamp.
+	// The format is 'mem_20060102150405[_<microseconds>].prof'.
+	// Microseconds are included if the interval is less than one second to avoid duplicate names.
+	// If false, filenames follow an incremental format: 'mem_<n>.prof'.
+	UseTimestamp bool
+
+	APIOpts map[string]any
 }
 
 // StartMemoryProfiling starts memory profiling in the specified directory.
@@ -171,16 +178,38 @@ func (cS *CoreService) StartMemoryProfiling(params MemoryProfilingParams) error
 	return nil
 }
 
+// newMemProfNameFunc returns a closure that generates memory profile filenames.
+func newMemProfNameFunc(interval time.Duration, useTimestamp bool) func() string {
+	if !useTimestamp {
+		i := 0
+		return func() string {
+			i++
+			return fmt.Sprintf("mem_%d.prof", i)
+		}
+	}
+	if interval < time.Second {
+		return func() string {
+			now := time.Now()
+			return fmt.Sprintf("mem_%s_%d.prof", now.Format("20060102150405"), now.Nanosecond()/1e3)
+		}
+	}
+
+	return func() string {
+		return fmt.Sprintf("mem_%s.prof", time.Now().Format("20060102150405"))
+	}
+}
+
 // profileMemory runs the memory profiling loop, writing profiles to files at the specified interval.
 func (cS *CoreService) profileMemory(params MemoryProfilingParams) {
 	defer cS.shdWg.Done()
+	fileName := newMemProfNameFunc(params.Interval, params.UseTimestamp)
 	ticker := time.NewTicker(params.Interval)
 	defer ticker.Stop()
 	files := make([]string, 0, params.MaxFiles)
 	for {
 		select {
 		case <-ticker.C:
-			path := filepath.Join(params.DirPath, fmt.Sprintf("mem_%s.prof", time.Now().Format("20060102150405"))) // mem20060102150405.prof
+			path := filepath.Join(params.DirPath, fileName())
 			if err := writeHeapProfile(path); err != nil {
 				utils.Logger.Err(fmt.Sprintf("<%s> %v", utils.CoreS, err))
 				cS.StopMemoryProfiling()