Supplier supplier = _supplierRepository.Get(id);

[ResponseType(typeof(Supplier))]
        public async Task<IHttpActionResult> GetSupplier(long id)
        {
            _supplierRepository.Get(id);
            Supplier supplier = await db.Suppliers.FindAsync(id);
            if (supplier == null)
            {
                return NotFound();
            }

            return Ok(supplier);
        }

 internal static Task<TResult> MakeMethodAsync<T, TResult>(Func<T, TResult> method, T param)
        {
            Task<TResult> task = new Task<TResult>(() => method(param));
            task.Start(); // Hot task (started task) should always be returned.
            return task;
        }

Supplier supplier = await MakeMethodAsync(_supplierRepository.Get, id);