System.Security.Claims.ClaimsPrincipal.AddIdentity C# (CSharp) Method

        public virtual void AddIdentity(ClaimsIdentity identity)
        {
            if (identity == null)
            {
                throw new ArgumentNullException(nameof(identity));
            }

            Contract.EndContractBlock();

            _identities.Add(identity);
        }

        public override ClaimsPrincipal Authenticate(string resourceName, ClaimsPrincipal incomingPrincipal)
        {
            var id = new ClaimsIdentity("ClaimsAuthenticationManager");
            id.AddClaim(new Claim(ClaimTypes.Role, "RoleFromClaimsAuthManager", null, "ClaimsAuthenticationManagerMock"));
            incomingPrincipal.AddIdentity(id);

            return incomingPrincipal;
        }