Bit.Core.Identity.JwtBearerSignInManager.SignInAsync C# (CSharp) Method

        private async Task<string> SignInAsync(User user, bool twoFactor)
        {
            var handler = new System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler();

            DateTime? tokenExpiration = null;
            var userPrincipal = await CreateUserPrincipalAsync(user);
            if(twoFactor)
            {
                userPrincipal.Identities.First().AddClaim(new Claim(ClaimTypes.AuthenticationMethod, JwtIdentityOptions.TwoFactorAuthenticationMethod));
                if(JwtIdentityOptions.TwoFactorTokenLifetime.HasValue)
                {
                    tokenExpiration = DateTime.UtcNow.Add(JwtIdentityOptions.TwoFactorTokenLifetime.Value);
                }
            }
            else
            {
                userPrincipal.Identities.First().AddClaim(new Claim(ClaimTypes.AuthenticationMethod, JwtIdentityOptions.AuthenticationMethod));
                if(JwtIdentityOptions.TokenLifetime.HasValue)
                {
                    tokenExpiration = DateTime.UtcNow.Add(JwtIdentityOptions.TokenLifetime.Value);
                }
            }

            var descriptor = new SecurityTokenDescriptor
            {
                Issuer = JwtIdentityOptions.Issuer,
                SigningCredentials = JwtIdentityOptions.SigningCredentials,
                Audience = JwtIdentityOptions.Audience,
                Subject = userPrincipal.Identities.First(),
                Expires = tokenExpiration
            };

            var securityToken = handler.CreateToken(descriptor);

            return handler.WriteToken(securityToken);
        }