Add Embed Provider Structure into EmbedBuilder

src/Discord.Net.Core/Entities/Messages/Embed.cs

@@ -57,7 +57,7 @@ namespace Discord
             Fields = fields;
         }
 
-        public int Length => Title?.Length + Author?.Name?.Length + Description?.Length + Footer?.Text?.Length + Fields.Sum(f => f.Name.Length + f.Value.ToString().Length) ?? 0;
+        public int Length => Title?.Length + Author?.Name?.Length + Description?.Length + Footer?.Text?.Length + Provider?.Name?.Length + Fields.Sum(f => f.Name.Length + f.Value.ToString().Length) ?? 0;
 
         public override string ToString() => Title;
         private string DebuggerDisplay => $"{Title} ({Type})";

src/Discord.Net.Core/Entities/Messages/EmbedProvider.cs

@@ -6,8 +6,8 @@ namespace Discord
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public struct EmbedProvider
     {
-        public string Name { get; }
-        public string Url { get; }
+        public string Name { get; internal set; }
+        public string Url { get; internal set; }
 
         internal EmbedProvider(string name, string url)
         {

src/Discord.Net.Rest/Entities/Messages/EmbedBuilder.cs

@@ -71,6 +71,7 @@ namespace Discord
 
         public EmbedAuthorBuilder Author { get; set; }
         public EmbedFooterBuilder Footer { get; set; }
+        public EmbedProviderBuilder Provider { get; set; }
         private List<EmbedFieldBuilder> _fields;
         public List<EmbedFieldBuilder> Fields
         {
@@ -171,6 +172,31 @@ namespace Discord
             return this;
         }
 
+        public EmbedBuilder WithProvider(EmbedProviderBuilder provider)
+        {
+            Provider = provider;
+            return this;
+        }
+
+        public EmbedBuilder WithProvider(Action<EmbedProviderBuilder> action)
+        {
+            var provider = new EmbedProviderBuilder();
+            action(provider);
+            Provider = provider;
+            return this;
+        }
+
+        public EmbedBuilder WithProvider(string name, string url = null)
+        {
+            var provider = new EmbedProviderBuilder
+            {
+                Name = name,
+                Url = url
+            };
+            Provider = provider;
+            return this;
+        }
+
         public EmbedBuilder AddField(string name, object value, bool inline = false)
         {
             var field = new EmbedFieldBuilder()
@@ -203,6 +229,7 @@ namespace Discord
         {
             _embed.Footer = Footer?.Build();
             _embed.Author = Author?.Build();
+            _embed.Provider = Provider?.Build();
             var fields = ImmutableArray.CreateBuilder<EmbedField>(Fields.Count);
             for (int i = 0; i < Fields.Count; i++)
                 fields.Add(Fields[i].Build());
@@ -376,4 +403,39 @@ namespace Discord
         public EmbedFooter Build()
             => _footer;
     }
+
+    public class EmbedProviderBuilder
+    {
+        private EmbedProvider _provider;
+
+        public string Name
+        {
+            get => _provider.Name;
+            set => _provider.Name = value;
+        }
+
+        public string Url
+        {
+            get => _provider.Url;
+            set
+            {
+                if (!value.IsNullOrUri()) throw new ArgumentException("Url must be a well-formed URI", nameof(Url));
+            }
+        }
+
+        public EmbedProviderBuilder WithName(string name)
+        {
+            Name = name;
+            return this;
+        }
+
+        public EmbedProviderBuilder WithUrl(string url)
+        {
+            Url = url;
+            return this;
+        }
+
+        public EmbedProvider Build()
+            => _provider;
+    }
 }

src/Discord.Net.Rest/Extensions/EmbedBuilderExtensions.cs

@@ -43,6 +43,11 @@ namespace Discord
                     IconUrl = embed.Footer?.IconUrl
                 },
                 ImageUrl = embed.Image?.Url,
+                Provider = new EmbedProviderBuilder
+                {
+                    Name = embed.Provider?.Name,
+                    Url = embed.Provider?.Url
+                },
                 ThumbnailUrl = embed.Thumbnail?.Url,
                 Timestamp = embed.Timestamp,
                 Title = embed.Title,