NewTransferQueue builds a TransferQueue, direction and underlying mechanism determined by adapter.

TransferQueue organises the wider process of uploading and downloading, including calling the API, passing the actual transfer request to transfer adapters, and dealing with progress, errors and retries.

Result of a transfer returned through CompletionChannel().

Adapter is implemented by types which can upload and/or download LFS file content to a remote store.

Env is any object with a config.Environment interface.

NewAdapterFunc creates new instances of Adapter.