Experiment with higher parallelism for drive

src/internal/kopia/wrapper.go

@@ -294,12 +294,17 @@ func (w Wrapper) makeSnapshotWithRoot(
 				Path: root.Name(),
 			}
 
+			parallelism := policy.OptionalInt(10)
+
 			trueVal := policy.OptionalBool(true)
 			errPolicy := &policy.Policy{
 				ErrorHandlingPolicy: policy.ErrorHandlingPolicy{
 					IgnoreFileErrors:      &trueVal,
 					IgnoreDirectoryErrors: &trueVal,
 				},
+				UploadPolicy: policy.UploadPolicy{
+					MaxParallelFileReads: &parallelism,
+				},
 			}
 
 			policyTree, err := policy.TreeForSourceWithOverride(innerCtx, w.c, si, errPolicy)

src/internal/m365/collection/drive/collection.go

@@ -471,7 +471,7 @@ func (oc *Collection) streamItems(ctx context.Context, errs *fault.Bus) {
 		int64(len(oc.driveItems)))
 	defer close(folderProgress)
 
-	semaphoreCh := make(chan struct{}, graph.Parallelism(path.OneDriveService).Item())
+	semaphoreCh := make(chan struct{}, 8)
 	defer close(semaphoreCh)
 
 	ctx = clues.Add(ctx,