NewLayerDownloadManager returns a new LayerDownloadManager.

NewLayerUploadManager returns a new LayerUploadManager.

NewTransfer creates a new transfer.

NewTransferManager returns a new TransferManager.

DoNotRetry is an error wrapper indicating that the error cannot be resolved with a retry.

LayerDownloadManager figures out which layers need to be downloaded, then registers and downloads those, taking into account dependencies between layers.

LayerUploadManager provides task management and progress reporting for uploads.

Watcher is returned by Watch and can be passed to Release to stop watching.

A DownloadDescriptor references a layer that may need to be downloaded.

DownloadDescriptorWithRegistered is a DownloadDescriptor that has an additional Registered method which gets called after a downloaded layer is registered.

Transfer represents an in-progress transfer.

TransferManager is used by LayerDownloadManager and LayerUploadManager to schedule and deduplicate transfers.

An UploadDescriptor references a layer that may need to be uploaded.

DoFunc is a function called by the transfer manager to actually perform a transfer.