ProtocolInstance Class

public abstract class ProtocolInstance : ProtocolSocket

using System;
using System.Threading.Tasks;
using Demo3D.Net;

namespace Examples.Net.ExampleProtocol {
    /// <summary>
    /// An interface that describes the services (the IO methods) that your protocol supports.
    /// Typically a protocol would implement one of the standard services (such as <see cref="IPacketIOService"/>).
    /// </summary>
    interface IExampleService {
        // Put whatever methods users of your protocol would expect in here.
    }

    /// <summary>
    /// An instance of a protocol.  Must inherit from <see cref="ProtocolInstance"/>, and should
    /// support a set of services.  The simplest way to support services is to implement the
    /// services interface (<see cref="IExampleService"/>) and to advertise those services in the
    /// <see cref="ExampleProtocol.NewInstance(ProtocolHead, ProtocolAddress)"/> constructor.
    /// </summary>
    /// <remarks>
    /// See <see cref="TCPExample.Client.TcpClientProtocol.TcpClientConnection"/> for an
    /// example implementing the TCP protocol.
    /// </remarks>
    public class ExampleProtocolInstance : ProtocolInstance, IExampleService {
        public ExampleProtocolInstance(Protocol protocol, ProtocolHead head, ProtocolAddress address) : base(protocol, head, address, false, null) { }

        /// <summary>
        /// Initializes the socket.
        /// </summary>
        /// <param name="sync">If true, the Task returned must be guaranteed to be complete.</param>
        protected override Task InitializeAsync(bool sync) {
            // Any initialization code goes here.
            return Task.CompletedTask;
        }

        /// <summary>
        /// Indicates whether the instance is still running.
        /// </summary>
        protected override bool InternalRunning => base.InternalRunning;  // Return true if the connection is established

        /// <summary>
        /// Opens or reopens the instance.
        /// </summary>
        /// <param name="sync">If true, the Task returned must be guaranteed to be complete.</param>
        /// <param name="flags">Additional flags.</param>
        protected override Task InternalOpenAsync(bool sync, Flags flags) {
            // Open your connection here.
            return Task.CompletedTask;
        }

        /// <summary>
        /// Forcibly shuts down the underlying protocol, causing all other users to throw an error.
        /// </summary>
        protected override Task InternalShutdownAsync(bool sync) {
            // Forcibly shut the connection down.
            return Task.CompletedTask;
        }

        /// <summary>
        /// Performs a controlled close.
        /// </summary>
        protected override Task InternalCloseAsync(bool sync) {
            // Called to close the connection.
            return InternalShutdownAsync(sync);
        }

        // Implement any IExampleService methods here.
    }

    /// <summary>
    /// A protocol inherits from <see cref="Protocol"/>.
    /// </summary>
    /// See <see cref="TCPExample.Client.TcpClientProtocol"/> for an example implementing the TCP protocol,
    /// or <see cref="TCPExample.Server.TcpServerProtocol"/> for an example implementing a TCP server.
    /// </remarks>
    sealed class ExampleProtocol : Protocol {
        /// <summary>
        /// Constructs a new protocol.
        /// You need to give your protocol a name, and advertise which services it supports.
        /// </summary>
        public ExampleProtocol() : base("Example", typeof(IExampleService)) { }

        /// <summary>
        /// Create a new server/client protocol instance.
        /// At the minimum, you need to implement this method to return a new instance of your protocol.
        /// </summary>
        /// <param name="head">The socket head which is a required parameter to the ProtocolInstance constructor.</param>
        /// <param name="protocolAddress">The protocol address.</param>
        /// <returns>A new ProtocolInstance.</returns>
        protected override ProtocolInstance NewInstance(ProtocolHead head, ProtocolAddress protocolAddress) {
            return new ExampleProtocolInstance(this, head, protocolAddress);
        }

        /// <summary>
        /// Registers the protocol with Demo3D.Net.
        /// You need to call this method somewhere in your code in order to register this protocol with Demo3D.Net.
        /// </summary>
        public static IDisposable Register() => Registry.Register(new ExampleProtocol());
    }
}