Short-circuit empty span

Author: Joy-less

src/LinkDotNet.StringBuilder/ValueStringBuilder.Append.cs

@@ -64,6 +64,11 @@ public void Append<T>(T value, ReadOnlySpan<char> format = default, int bufferSi
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void Append(scoped ReadOnlySpan<char> str)
     {
+        if (str.IsEmpty)
+        {
+            return;
+        }
+
         var newSize = str.Length + bufferPosition;
         if (newSize > buffer.Length)
         {
@@ -160,6 +165,11 @@ public void AppendLine(scoped ReadOnlySpan<char> str)
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public Span<char> AppendSpan(int length)
     {
+        if (length == 0)
+        {
+            return [];
+        }
+
         var origPos = bufferPosition;
         if (origPos > buffer.Length - length)
         {

src/LinkDotNet.StringBuilder/ValueStringBuilder.Insert.cs

@@ -66,6 +66,11 @@ public void Insert(int index, scoped ReadOnlySpan<char> value)
             throw new ArgumentOutOfRangeException(nameof(index), "The given index can't be bigger than the string itself.");
         }
 
+        if (value.IsEmpty)
+        {
+            return;
+        }
+
         var newLength = bufferPosition + value.Length;
         if (newLength > buffer.Length)
         {