let authenticationData = {
            Username: username,
            Password: password,
        };
        let authenticationDetails = new AWSCognito.CognitoIdentityServiceProvider.AuthenticationDetails(authenticationData);

        let userData = {
            Username: username,
            Pool: this.cUtil.getUserPool()
        };

        console.log("Authenticating the user");
        let cognitoUser = new AWSCognito.CognitoIdentityServiceProvider.CognitoUser(userData);
        cognitoUser.authenticateUser(authenticationDetails, {
            onSuccess: function (result) {
                var logins = {};
                var loginKey = 'cognito-idp.' +
                                _REGION +
                                '.amazonaws.com/' +
                                _USER_POOL_ID;
                console.log("identity pool id: " + _IDENTITY_POOL_ID);
                console.log("login key: " + loginKey);
                console.log("user: " + JSON.stringify(cognitoUser));
                logins[loginKey] = result.getIdToken().getJwtToken();
                console.log("logins: " + JSON.stringify(logins));
                AWS.config.credentials = new AWS.CognitoIdentityCredentials({
                    'IdentityPoolId': _IDENTITY_POOL_ID,
                    'Logins': logins
                });