Introduce disk io stats metrics (#15512)

internal/disk/stat_freebsd.go

@@ -21,6 +21,7 @@
 package disk
 
 import (
+	"errors"
 	"fmt"
 	"syscall"
 )
@@ -46,3 +47,8 @@ func GetInfo(path string) (info Info, err error) {
 	info.Used = info.Total - info.Free
 	return info, nil
 }
+
+// GetAllDrivesIOStats returns IO stats of all drives found in the machine
+func GetAllDrivesIOStats() (info AllDrivesIOStats, err error) {
+	return nil, errors.New("operation unsupported")
+}