static async Task <R> Bind <R>(CancellationToken cancellationToken, Expression <Func <R> > bind)
{
var mce = (MethodCallExpression)bind.Body;
IQueryable query = (IQueryable)ExpressionEvaluator.Eval(mce.Arguments.FirstEx()) !;
List <Expression> otherExpressions = mce.Arguments.Skip(1).Select(a => (Expression)ExpressionEvaluator.Eval(a) !).ToList();
var mc2 = Expression.Call(mce.Method, otherExpressions.PreAnd(query.Expression));
var provider = (IQueryProviderAsync)query.Provider;
var value = await provider.ExecuteAsync(mc2, cancellationToken);
return((R)value !);
}