/// <summary>
        /// Creates a new item change observable for OPC item, specifying machine name, server class, item ID, requested update 
        /// rate, and percent deadband.
        /// </summary>
        /// <param name="endpointDescriptor">Endpoint descriptor. Identifies the OPC-UA server.</param>
        /// <param name="nodeDescriptor">Node descriptor. Identifies the node in OPC server's address space.</param>
        /// <param name="samplingInterval">The sampling interval (in milliseconds) indicates the fastest rate at which the 
        /// Server should sample its underlying source for data changes.</param>
        /// <param name="absoluteDeadbandValue">The value of absolute deadband.</param>
        /// <returns>Returns an observable for changes in the given OPC item.</returns>
        /// <remarks>
        /// The <see cref="UAReactive.DefaultClientSelector"/> selector will be used for OPC Unified Architecture operations.
        /// </remarks>
        [NotNull]
        [SuppressMessage("Microsoft.Design", "CA1026:DefaultParametersShouldNotBeUsed")]    // intentional (advanced usage type)
        static public UAMonitoredItemChangedObservable<TValue> Create<TValue>(
            [NotNull] UAEndpointDescriptor endpointDescriptor,
            [NotNull] UANodeDescriptor nodeDescriptor, 
            int samplingInterval, 
            double absoluteDeadbandValue= 0.0F)

/// <summary>
        /// Creates a new item change observable for OPC item given by OPC server and item descriptors, and OPC group parameters
        /// object.
        /// </summary>
        /// <param name="endpointDescriptor">Endpoint descriptor. Identifies the OPC-UA server.</param>
        /// <param name="nodeDescriptor">Node descriptor. Identifies the node in OPC server's address space.</param>
        /// <param name="monitoringParameters">Contains monitoring parameters (such as the sampling interval, and optional 
        /// 	data change filter).</param>
        /// <param name="subscriptionParameters">Contains subscription parameters (such as the publishing interval).</param>
        /// <param name="state">The state object (can be any object supplied by your code); available in notifications. </param>
        /// <returns>Returns an observable for changes in the given OPC item.</returns>
        /// <remarks>
        /// The <see cref="UAReactive.DefaultClientSelector"/> selector will be used for OPC Unified Architecture operations.
        /// </remarks>
        [NotNull]
        [SuppressMessage("Microsoft.Design", "CA1026:DefaultParametersShouldNotBeUsed")]    // intentional (advanced usage type)
        static public UAMonitoredItemChangedObservable<TValue> Create<TValue>(
            [NotNull] UAEndpointDescriptor endpointDescriptor,
            [NotNull] UANodeDescriptor nodeDescriptor, 
            [NotNull] UAMonitoringParameters monitoringParameters,
            [NotNull] UASubscriptionParameters subscriptionParameters,
            [CanBeNull] object state = null)
 

 
        /// <summary>
        /// Creates a new item change observable for OPC item given by <see cref="UAMonitoredItemArguments"/> object.
        /// </summary>
        /// <param name="args">Contains an OPC server and item descriptors, and OPC group parameters.</param>
        /// <returns>Returns an observable for changes in the given OPC item.</returns>
        /// <remarks>
        /// The <see cref="UAReactive.DefaultClientSelector"/> selector will be used for OPC Unified Architecture operations.
        /// </remarks>
        [NotNull]
        static public UAMonitoredItemChangedObservable<TValue> Create<TValue>([NotNull] UAMonitoredItemArguments args)