perf: multi-thread downloader, Content-Disposition (#4921)

general: enhance multi-thread downloader with cancelable context, immediately stop all stream processes when canceled;
feat(crypt): improve stream closing;
general: fix the bug of downloading files becomes previewing stream on modern browsers;

Co-authored-by: Sean He <866155+seanhe26@users.noreply.github.com>
Co-authored-by: Andy Hsu <i@nn.ci>

internal/model/args.go

@@ -2,6 +2,7 @@ package model
 
 import (
 	"github.com/alist-org/alist/v3/pkg/http_range"
+	"github.com/alist-org/alist/v3/pkg/utils"
 	"io"
 	"net/http"
 	"time"
@@ -45,7 +46,7 @@ type FsOtherArgs struct {
 }
 type RangeReadCloser struct {
 	RangeReader RangeReaderFunc
-	Closer      io.Closer
+	Closers     *utils.Closers
 }
 
 type WriterFunc func(w io.Writer) error