* querylog: better errors

internal/querylog/qlog_file.go

@@ -1,7 +1,6 @@
 package querylog
 
 import (
-	"errors"
 	"io"
 	"os"
 	"sync"
@@ -11,12 +10,12 @@ import (
 	"github.com/AdguardTeam/golibs/log"
 )
 
-// ErrSeekNotFound is returned from the Seek method
-// if we failed to find the desired record
-var ErrSeekNotFound = errors.New("Seek not found the record")
+// ErrSeekNotFound is returned from Seek if when it fails to find the requested
+// record.
+const ErrSeekNotFound agherr.Error = "seek: record not found"
 
-// ErrEndOfLog is returned when the end of the current log is reached.
-var ErrEndOfLog agherr.Error = "end of log"
+// ErrEndOfLog is returned from Seek when the end of the current log is reached.
+const ErrEndOfLog agherr.Error = "seek: end of log"
 
 // TODO: Find a way to grow buffer instead of relying on this value when reading strings
 const maxEntrySize = 16 * 1024