private string GenerateSignature(Dictionary <string, string> authorizationComponents)
{
var normalizedParams = OAuth.NormalizeParams(authorizationComponents.ToList());
var url = $"{_oneRosterApiUrl}/token";
var signatureBaseString = $"GET&{Uri.EscapeDataString(url)}&{normalizedParams}";
return(OAuth.GenerateHmac(signatureBaseString, "HMAC-SHA1", _oneRosterSecret));
}