Signature invalid if metadata contains two consecutive spaces

[WolfspiritM]

Hi,

When using MetaData that contains two consecutive spaces the signature doesn't match with the calulcated server signature.

var metaData = new Dictionary<string, string>()
{
    {"X-Amz-Meta-Test", "Test  Test"}
};
await minio.PutObjectAsync("bucket",
                           "test",
                           filestream,
                           filestream.Length,
                           "application/octet-stream",
                            metaData);

MinioException: Minio API responded with message=The request signature we calculated does not match the signature you provided. Check your key and signing method

The minio server contains the following go function to create a signature based on signed headers.

// Trim leading and trailing spaces and replace sequential spaces with one space, following Trimall()
// in http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
func signV4TrimAll(input string) string {
	// Compress adjacent spaces (a space is determined by
	// unicode.IsSpace() internally here) to one space and return
	return strings.Join(strings.Fields(input), " ")
}

The minio-dotnet library however calcucates the siganture without removing additional spaces.

If that is true, then this issue needs to be opened in the other libs aswell as I think at least minio-go and minio-js don't have anything related to trimAll, too.

[kannappanr]

@WolfspiritM Thanks for filing this issue. We will test this out and fix it.