fix(stream): allow seeking beyond file size per Go convention (#2667)

Remove `offset > size` guard from RangeReadReadAtSeeker.Seek and
DynamicReadAtSeeker.Seek. Go's io.Seeker convention allows seeking
past EOF.

Co-authored-by: Pikachu Ren <40362270+PIKACHUIM@users.noreply.github.com>

Author: Ovear

internal/stream/stream.go

@@ -519,7 +519,7 @@ func (r *RangeReadReadAtSeeker) Seek(offset int64, whence int) (int64, error) {
 	default:
 		return 0, errors.New("Seek: invalid whence")
 	}
-	if offset < 0 || offset > r.ss.GetSize() {
+	if offset < 0 {
 		return 0, errors.New("Seek: invalid offset")
 	}
 	r.masterOff = offset

pkg/buffer/utils.go

@@ -79,7 +79,7 @@ func (r *DynamicReadAtSeeker) Seek(offset int64, whence int) (int64, error) {
 		return 0, errors.New("Seek: invalid whence")
 	}
 
-	if offset < 0 || offset > r.block.Size() {
+	if offset < 0 {
 		return 0, errors.New("Seek: invalid offset")
 	}
 	r.offset = offset