delete(metadata, k)
		}
	}

	if contentEncoding, ok := metadata[strings.ToLower(xhttp.ContentEncoding)]; ok {
		contentEncoding = trimAwsChunkedContentEncoding(contentEncoding)
		if contentEncoding != "" {
			// Make sure to trim and save the content-encoding
			// parameter for a streaming signature which is set
			// to a custom value for example: "aws-chunked,gzip".