Fix Bedrock.Framework nullability issues. (#163)

* Fix Bedrock.Framework nullability issues. And introduced a property to store whether the `ProtocolReadResult` was faulty or not.

* Remove IsFaulted

src/Bedrock.Framework/Middleware/Tls/TlsOptions.cs

@@ -34,7 +34,7 @@ public TlsOptions()
         /// If the certificate has an Extended Key Usage extension, the usages must include Server Authentication (OID 1.3.6.1.5.5.7.3.1).
         /// </para>
         /// </summary>
-        public X509Certificate2 LocalCertificate { get; set; }
+        public X509Certificate2? LocalCertificate { get; set; }
 
         /// <summary>
         /// <para>
@@ -45,7 +45,7 @@ public TlsOptions()
         /// If the certificate has an Extended Key Usage extension, the usages must include Server Authentication (OID 1.3.6.1.5.5.7.3.1).
         /// </para>
         /// </summary>
-        public Func<ConnectionContext, string, X509Certificate2> LocalServerCertificateSelector { get; set; }
+        public Func<ConnectionContext, string, X509Certificate2>? LocalServerCertificateSelector { get; set; }
 
         /// <summary>
         /// Specifies the remote endpoint certificate requirements for a TLS connection. Defaults to <see cref="RemoteCertificateMode.RequireCertificate"/>.
@@ -56,7 +56,7 @@ public TlsOptions()
         /// Specifies a callback for additional remote certificate validation that will be invoked during authentication. This will be ignored
         /// if <see cref="AllowAnyRemoteCertificate"/> is called after this callback is set.
         /// </summary>
-        public RemoteCertificateValidator RemoteCertificateValidation { get; set; }
+        public RemoteCertificateValidator? RemoteCertificateValidation { get; set; }
 
         /// <summary>
         /// Specifies allowable SSL protocols. Defaults to <see cref="System.Security.Authentication.SslProtocols.Tls12" /> and <see cref="System.Security.Authentication.SslProtocols.Tls11"/>.
@@ -85,13 +85,13 @@ public void AllowAnyRemoteCertificate()
         /// Provides direct configuration of the <see cref="SslServerAuthenticationOptions"/> on a per-connection basis.
         /// This is called after all of the other settings have already been applied.
         /// </summary>
-        public Action<ConnectionContext, SslServerAuthenticationOptions> OnAuthenticateAsServer { get; set; }
+        public Action<ConnectionContext, SslServerAuthenticationOptions>? OnAuthenticateAsServer { get; set; }
 
         /// <summary>
         /// Provides direct configuration of the <see cref="SslClientAuthenticationOptions"/> on a per-connection basis.
         /// This is called after all of the other settings have already been applied.
         /// </summary>
-        public Action<ConnectionContext, SslClientAuthenticationOptions> OnAuthenticateAsClient { get; set; }
+        public Action<ConnectionContext, SslClientAuthenticationOptions>? OnAuthenticateAsClient { get; set; }
 
         /// <summary>
         /// Specifies the maximum amount of time allowed for the TLS/SSL handshake. This must be positive and finite.

src/Bedrock.Framework/Protocols/ProtocolReadResult.cs

@@ -1,5 +1,9 @@
 namespace Bedrock.Framework.Protocols
 {
+    /// <summary>
+    /// Represents a reading result from <see cref="ProtocolReader"/>.
+    /// </summary>
+    /// <typeparam name="TMessage">The read message.</typeparam>
     public readonly struct ProtocolReadResult<TMessage>
     {
         public ProtocolReadResult(TMessage message, bool isCanceled, bool isCompleted)
@@ -9,8 +13,19 @@ public ProtocolReadResult(TMessage message, bool isCanceled, bool isCompleted)
             IsCompleted = isCompleted;
         }
 
+        /// <summary>
+        /// The read message.
+        /// </summary>
         public TMessage Message { get; }
+
+        /// <summary>
+        /// Whether the reading operation was cancelled (true) or not (false).
+        /// </summary>
         public bool IsCanceled { get; }
+
+        /// <summary>
+        /// Whether the reading operation was completed (true) or not (false). 
+        /// </summary>
         public bool IsCompleted { get; }
     }
 }