- The multiple-file transfer functions now accept vectors as their source and destination arguments. Each element of the source can be a filename, or a wildcard expanding to multiple files, eg `multiupload_adls_file(container, c("file1", "name.*", "*.csv"), "destdir")`. Th destination should be either a single name giving the destination directory, or a vector of file/pathnames with one element for each file transferred. See the examples for more details.
- Creating a service-specific endpoint (`file_endpoint`, `blob_endpoint`, `adls_endpoint`) with an invalid URL will now warn, instead of throwing an error. This enables using tools like Azurite, which use a local address as the endpoint. Calling `storage_endpoint` with an invalid URL will still throw an error, as the function has no way of telling which storage service is required.
- Remove the warning about ADLSgen2 not supporting shared access signatures (SAS).
- Background process pool functionality has been moved to AzureRMR. This removes code duplication, and also makes it available for other packages that may benefit.
- Fix a bug in confirmation prompts. On R >= 3.5, prompts will now use `utils::askYesNo`; as a side-effect, Windows users who are using RGUI.exe will see a popup dialog box instead of a message in the terminal.
- Add `copy_url_to_blob` function, for directly copying a HTTP\[S\] URL to blob storage. The corresponding generic is `copy_url_to_storage`, with a method for blob containers (only).
- By default, HTTP(S) requests to the storage endpoint will now be retried on encountering a network error. To change the number of retries, call `options(azure_storage_retries=N)` where N >= 0. Setting this option to zero disables retrying.
- Downloading now proceeds in blocks, much like uploading. The default block size is set to 16MB for blob and ADLSgen2, and 4MB for file storage. While this reduces the throughput slightly (basically there is at least one extra REST call involved), it allows retrying a failed transfer on a per-block basis rather than having to redownload the entire file.
* Support uploading and downloading to in-memory R objects, without having to create a temporary file. Uploading can be done with `src` a `rawConnection` or `textConnection` object. For downloading, if `dest` is `NULL`, the downloaded data is returned as a raw vector, or if `dest` is a `rawConnection`, in the connection object. See the examples in the documentation.
* Implement parallel file transfers using a background pool of R processes. This can significantly speed up transfers when working with multiple small files.
* Experimental support for using the Microsoft AzCopy commandline utility to perform file transfers. Set the argument `use_azcopy=TRUE` in any upload or download function to call AzCopy rather than relying on internal R code. The `call_azcopy` function also allows you to run AzCopy with arbitrary arguments. Requires [AzCopy version 10](https://github.com/Azure/azure-storage-azcopy).
