This release supports adding a Host header to a request in order to override the normal behavior of the extension which extracts the host from the request URI. This allows requests to tunnel through proxies while still using the correct endpoint host for calculating the AWS signature.
The release also adds support for optionally (via an extension setting) using the X-Amz-Content-Sha256 to have a header provide the digest of the request contents rather than have the extension calculate the value based on the body contents. This allows requests that contains binary data to properly include content hashes as the extension only sees body content as strings.