/// <summary>
        /// Produce a <see cref="ContractCollection"/> containing all contracts found in the provided XML <paramref name="element"/>.
        /// </summary>
        /// <param name="element">The XML element to parse.</param>
        /// <returns>A contract collection containing the contracts found in the XML element.</returns>
        /// <exception cref="ContractParseException">Parsing failed.</exception>
        public static ContractCollection FromXml(XElement element)
        {
            var bindActions = new List <Action>();

            var collection = new ContractCollection {
                AllowResolution = false
            };

            foreach (var el in element.Elements())
            {
                var id = el.Attribute("Id")?.Value;

                if (string.IsNullOrWhiteSpace(id))
                {
                    throw new ContractParseException("Contract XML element must contain a non-empty \"Id\" attribute.");
                }

                ByRefContract contract;
                switch (el.Name.LocalName)
                {
                case "ComplexRead":
                    contract = new ComplexReadContract(el, collection.ResolveReadContract, bindActions);
                    break;

                case "ComplexWrite":
                    contract = new ComplexWriteContract(el, collection.ResolveWriteContract, bindActions);
                    break;

                case "UnionRead":
                    contract = new UnionReadContract(el, collection.ResolveReadContract, bindActions);
                    break;

                case "UnionWrite":
                    contract = new UnionWriteContract(el, collection.ResolveWriteContract, bindActions);
                    break;

                case "Enum":
                    contract = new EnumContract(el);
                    break;

                default:
                    throw new ContractParseException($"Unsupported contract XML element with name \"{el.Name.LocalName}\".");
                }

                contract.Id = id;

                collection._contracts.Add(contract);
            }

            collection.AllowResolution = true;

            foreach (var bindAction in bindActions)
            {
                bindAction();
            }

            return(collection);
        }
        /// <summary>
        /// Get or create a write contract for <paramref name="type"/>.
        /// </summary>
        /// <param name="type">The type to get or create a write contract for.</param>
        /// <returns>The write contract corresponding to <paramref name="type"/>.</returns>
        public IWriteContract GetOrAddWriteContract(Type type)
        {
            if (type == typeof(Empty))
            {
                return(Intern(new EmptyContract()));
            }
            if (PrimitiveContract.CanProcess(type))
            {
                return(Intern(new PrimitiveContract(type)));
            }
            if (EnumContract.CanProcess(type))
            {
                return(Intern(new EnumContract(type)));
            }
            if (TupleWriteContract.CanProcess(type))
            {
                return(Intern(new TupleWriteContract(type, this)));
            }
            if (NullableWriteContract.CanProcess(type))
            {
                return(Intern(new NullableWriteContract(type, this)));
            }
            if (ListWriteContract.CanProcess(type))
            {
                return(Intern(new ListWriteContract(type, this)));
            }
            if (DictionaryWriteContract.CanProcess(type))
            {
                return(Intern(new DictionaryWriteContract(type, this)));
            }
            if (UnionWriteContract.CanProcess(type))
            {
                return(Intern(new UnionWriteContract(type, this)));
            }

            return(Intern(new ComplexWriteContract(type, this)));
        }