Fix resharper warnings

.editorconfig

@@ -1 +1,8 @@
 root = true
+
+[*.cs]
+# CSharpier expects adds trailing comma, prevent editor from cleaning it up
+trailing_comma_in_multiline_lists = true
+
+[tests/**/*.cs]
+dotnet_diagnostic.CA2007.severity = none

Directory.Packages.props

@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageVersion Include="GitHubActionsTestLogger" Version="3.0.4" />
+    <PackageVersion Include="JetBrains.Annotations" Version="2025.2.4" />
     <PackageVersion Include="Microsoft.CodeAnalysis.PublicApiAnalyzers" Version="3.3.4" />
     <PackageVersion Include="Microsoft.Bcl.Memory" Version="10.0.7" />
     <PackageVersion Include="Microsoft.Extensions.FileProviders.Abstractions" Version="10.0.7" />
@@ -17,6 +18,7 @@
     <PackageVersion Include="PolySharp" Version="1.15.0" />
     <PackageVersion Include="System.Collections.Immutable" Version="10.0.7" />
     <PackageVersion Include="System.Linq.Async" Version="7.0.1" />
+    <PackageVersion Include="System.Text.Json" Version="10.0.7" />
     <PackageVersion Include="TUnit" Version="1.43.41" />
   </ItemGroup>
 </Project>

src/Usenet/Exceptions/InvalidNzbDataException.cs

@@ -1,7 +1,10 @@
-namespace Usenet.Exceptions;
+using JetBrains.Annotations;
+
+namespace Usenet.Exceptions;
 
 /// <inheritdoc />
 /// <summary>The exception that is thrown when a data stream or text is not in a valid nzb format.</summary>
+[PublicAPI]
 public class InvalidNzbDataException : Exception
 {
     /// <inheritdoc />

src/Usenet/Exceptions/InvalidYencDataException.cs

@@ -1,7 +1,10 @@
-namespace Usenet.Exceptions;
+using JetBrains.Annotations;
+
+namespace Usenet.Exceptions;
 
 /// <inheritdoc />
 /// <summary>The exception that is thrown when a data stream or text is not in a valid yEnc format.</summary>
+[PublicAPI]
 public class InvalidYencDataException : Exception
 {
     /// <inheritdoc />

src/Usenet/Exceptions/NntpException.cs

@@ -1,7 +1,10 @@
-namespace Usenet.Exceptions;
+using JetBrains.Annotations;
+
+namespace Usenet.Exceptions;
 
 /// <inheritdoc />
 /// <summary>The exception that is thrown when communicating using the Network News Transfer Protocol.</summary>
+[PublicAPI]
 public class NntpException : Exception
 {
     /// <inheritdoc />

src/Usenet/Logger.cs

@@ -1,4 +1,5 @@
-using Microsoft.Extensions.Logging;
+using JetBrains.Annotations;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 
 namespace Usenet;
@@ -7,6 +8,7 @@ namespace Usenet;
 /// Host for a singleton <see cref="ILoggerFactory"/>
 /// (<a href="https://stackify.com/net-core-loggerfactory-use-correctly/">Source</a>).
 /// </summary>
+[PublicAPI]
 public static class Logger
 {
     /// <summary>

src/Usenet/Nntp/Builders/NntpArticleBuilder.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using JetBrains.Annotations;
 using Microsoft.Extensions.Logging;
 using Usenet.Exceptions;
 using Usenet.Extensions;
@@ -10,6 +11,7 @@ namespace Usenet.Nntp.Builders;
 /// <summary>
 /// Represents a mutable <see cref="NntpArticle"/>.
 /// </summary>
+[PublicAPI]
 public class NntpArticleBuilder
 {
     private readonly ILogger _log = Logger.Create<NntpArticleBuilder>();
@@ -48,7 +50,7 @@ public NntpArticleBuilder InitializeFrom(NntpArticle article)
     {
         Guard.ThrowIfNull(article);
 
-        _messageId = new(article.MessageId.Value);
+        _messageId = new NntpMessageId(article.MessageId.Value);
         _groupsBuilder = new NntpGroupsBuilder().Add(article.Groups);
         _headers = [];
         _from = string.Empty;
@@ -326,13 +328,13 @@ public NntpArticle Build()
         _headers.Add(NntpHeaders.From, _from);
         _headers.Add(NntpHeaders.Subject, _subject);
 
-        if (_dateTime.HasValue)
-        {
-            var formattedDate = _dateTime
-                .Value.ToUniversalTime()
-                .ToString(DateFormat, CultureInfo.InvariantCulture);
-            _headers.Add(NntpHeaders.Date, $"{formattedDate} +0000");
-        }
+        if (!_dateTime.HasValue)
+            return new NntpArticle(0, _messageId, groups, _headers, _body);
+
+        var formattedDate = _dateTime
+            .Value.ToUniversalTime()
+            .ToString(DateFormat, CultureInfo.InvariantCulture);
+        _headers.Add(NntpHeaders.Date, $"{formattedDate} +0000");
 
         return new NntpArticle(0, _messageId, groups, _headers, _body);
     }

src/Usenet/Nntp/Builders/NntpGroupsBuilder.cs

@@ -1,4 +1,5 @@
-using Usenet.Nntp.Models;
+using JetBrains.Annotations;
+using Usenet.Nntp.Models;
 using Usenet.Nntp.Parsers;
 using Usenet.Util;
 
@@ -7,6 +8,7 @@ namespace Usenet.Nntp.Builders;
 /// <summary>
 /// Represents a mutable <see cref="NntpGroups"/>.
 /// </summary>
+[PublicAPI]
 public class NntpGroupsBuilder
 {
     private readonly List<string> _groups = [];
@@ -82,11 +84,6 @@ public NntpGroupsBuilder Remove(IEnumerable<string> values)
 
     private void AddGroups(IEnumerable<string> values)
     {
-        if (values == null)
-        {
-            return;
-        }
-
         foreach (var group in values)
         {
             if (!_groups.Contains(group))
@@ -98,11 +95,6 @@ private void AddGroups(IEnumerable<string> values)
 
     private void RemoveGroups(IEnumerable<string> values)
     {
-        if (values == null)
-        {
-            return;
-        }
-
         foreach (var group in values)
         {
             _groups.RemoveAll(g => g == group);

src/Usenet/Nntp/Contracts/INntpClient.cs

@@ -1,5 +1,8 @@
+using JetBrains.Annotations;
+
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClient
     : INntpClientRfc2980,
         INntpClientRfc3977,

src/Usenet/Nntp/Contracts/INntpClientCompression.cs

@@ -1,8 +1,10 @@
+using JetBrains.Annotations;
 using Usenet.Nntp.Models;
 using Usenet.Nntp.Responses;
 
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClientCompression
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientConnection.cs

@@ -1,7 +1,9 @@
+using JetBrains.Annotations;
 using Usenet.Nntp.Responses;
 
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClientConnection
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientPool.cs

@@ -1,8 +1,11 @@
+using JetBrains.Annotations;
+
 namespace Usenet.Nntp.Contracts;
 
 /// <summary>
 /// Represents a pool of authenticated NNTP clients.
 /// </summary>
+[PublicAPI]
 public interface INntpClientPool : IDisposable
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientRfc2980.cs

@@ -1,8 +1,10 @@
+using JetBrains.Annotations;
 using Usenet.Nntp.Models;
 using Usenet.Nntp.Responses;
 
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClientRfc2980
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientRfc3977.cs

@@ -1,10 +1,12 @@
 using System.Diagnostics.CodeAnalysis;
+using JetBrains.Annotations;
 using Usenet.Nntp.Models;
 using Usenet.Nntp.Responses;
 
 namespace Usenet.Nntp.Contracts;
 
 [SuppressMessage("Naming", "CA1716:Identifiers should not match keywords")]
+[PublicAPI]
 public interface INntpClientRfc3977
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientRfc4643.cs

@@ -1,5 +1,8 @@
+using JetBrains.Annotations;
+
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClientRfc4643
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpClientRfc6048.cs

@@ -1,7 +1,9 @@
+using JetBrains.Annotations;
 using Usenet.Nntp.Responses;
 
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface INntpClientRfc6048
 {
     /// <summary>

src/Usenet/Nntp/Contracts/INntpConnection.cs

@@ -1,3 +1,4 @@
+using JetBrains.Annotations;
 using Usenet.Nntp.Parsers;
 using Usenet.Util;
 
@@ -7,6 +8,7 @@ namespace Usenet.Nntp.Contracts;
 /// Represents an NNTP connection.
 /// Based on Kristian Hellang's NntpLib.Net project https://github.com/khellang/NntpLib.Net.
 /// </summary>
+[PublicAPI]
 public interface INntpConnection : IDisposable
 {
     /// <summary>

src/Usenet/Nntp/Contracts/IPooledNntpClient.cs

@@ -1,8 +1,11 @@
+using JetBrains.Annotations;
+
 namespace Usenet.Nntp.Contracts;
 
 /// <summary>
 /// An NNTP client for which connections and authentication are managed by a pool.
 /// </summary>
+[PublicAPI]
 public interface IPooledNntpClient
     : INntpClientRfc2980,
         INntpClientRfc3977,

src/Usenet/Nntp/Contracts/IPooledNntpClientLease.cs

@@ -1,5 +1,8 @@
+using JetBrains.Annotations;
+
 namespace Usenet.Nntp.Contracts;
 
+[PublicAPI]
 public interface IPooledNntpClientLease : IDisposable
 {
     public IPooledNntpClient Client { get; }

src/Usenet/Nntp/Models/NntpArticle.cs

@@ -1,4 +1,5 @@
 using System.Collections.Immutable;
+using JetBrains.Annotations;
 using Usenet.Util;
 using HashCode = Usenet.Util.HashCode;
 
@@ -7,6 +8,7 @@ namespace Usenet.Nntp.Models;
 /// <summary>
 /// Represents an NNTP article.
 /// </summary>
+[PublicAPI]
 public class NntpArticle : IEquatable<NntpArticle>
 {
     /// <summary>
@@ -42,25 +44,23 @@ public class NntpArticle : IEquatable<NntpArticle>
     /// <param name="groups">The NNTP newsgroups this <see cref="NntpArticle"/> is posted in.</param>
     /// <param name="headers">The headers of the <see cref="NntpArticle"/>.</param>
     /// <param name="body">The body of the <see cref="NntpArticle"/>.</param>
-    public NntpArticle(
+    internal NntpArticle(
         long number,
-        NntpMessageId? messageId,
-        NntpGroups? groups,
-        IDictionary<string, ICollection<string>>? headers,
-        IList<string>? body
+        NntpMessageId messageId,
+        NntpGroups groups,
+        IDictionary<string, ICollection<string>> headers,
+        IList<string> body
     )
     {
         Number = number;
-        MessageId = messageId ?? NntpMessageId.Empty;
-        Groups = groups ?? NntpGroups.Empty;
-        Headers = (
-            headers ?? MultiValueDictionary<string, string>.EmptyIgnoreCase
-        ).ToImmutableDictionary(
+        MessageId = messageId;
+        Groups = groups;
+        Headers = headers.ToImmutableDictionary(
             x => x.Key,
             x => x.Value.ToImmutableList(),
             keyComparer: StringComparer.OrdinalIgnoreCase
         );
-        Body = (body ?? []).ToImmutableList();
+        Body = body.ToImmutableList();
     }
 
     /// <summary>

src/Usenet/Nntp/Models/NntpArticleRange.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using JetBrains.Annotations;
 using Usenet.Util;
 using HashCode = Usenet.Util.HashCode;
 
@@ -12,6 +13,7 @@ namespace Usenet.Nntp.Models;
 /// <a href="https://tools.ietf.org/html/rfc2980#section-2.9">XPAT</a> and
 /// <a href="https://tools.ietf.org/html/rfc2980#section-2.11">XROVER</a> commands.
 /// </summary>
+[PublicAPI]
 public class NntpArticleRange : IEquatable<NntpArticleRange>
 {
     /// <summary>
@@ -29,7 +31,7 @@ public class NntpArticleRange : IEquatable<NntpArticleRange>
     /// </summary>
     /// <param name="from">The article number to start the range from.</param>
     /// <param name="to">The optional article number to end the range with.</param>
-    public NntpArticleRange(long from, long? to)
+    private NntpArticleRange(long from, long? to)
     {
         From = from;
         To = to;
@@ -47,28 +49,24 @@ public NntpArticleRange(long from, long? to)
     /// </summary>
     /// <param name="from">The article number to start the range from.</param>
     /// <returns>A new range containing the given article and all following.</returns>
-    public static NntpArticleRange AllFollowing(long from) => new(@from, null);
+    public static NntpArticleRange AllFollowing(long from) => new(from, null);
 
     /// <summary>
     /// Creates a range containing all articles between and including <paramref name="from"/> and <paramref name="to"/>.
     /// </summary>
     /// <param name="from">The article number to start the range from.</param>
     /// <param name="to">The article number to end the range with.</param>
     /// <returns>A new range containg all articles between and including <paramref name="from"/> and <paramref name="to"/>.</returns>
-    public static NntpArticleRange Range(long from, long to) => new(@from, to);
+    public static NntpArticleRange Range(long from, long to) => new(from, to);
 
     /// <summary>
     /// Returns the text representation of the value formatted according to the NNTP specifications.
     /// </summary>
     /// <returns>The text representation of the value formatted according to the NNTP specifications</returns>
     public override string ToString() =>
-        To == null
-            ? $"{From}-"
-            : (
-                To.Value == From
-                    ? From.ToString(CultureInfo.InvariantCulture)
-                    : $"{From}-{To.Value}"
-            );
+        To == null ? $"{From}-"
+        : To.Value == From ? From.ToString(CultureInfo.InvariantCulture)
+        : $"{From}-{To.Value}";
 
     /// <summary>
     /// Returns the hash code for this instance.

src/Usenet/Nntp/Models/NntpDateTime.cs

@@ -1,10 +1,12 @@
+using JetBrains.Annotations;
 using Usenet.Util;
 
 namespace Usenet.Nntp.Models;
 
 /// <summary>
 /// Represents an NNTP datetime object.
 /// </summary>
+[PublicAPI]
 public class NntpDateTime : IEquatable<NntpDateTime>
 {
     /// <summary>