Removed net6.0 and net7.0 from TargetFrameworks

Author: danzuep

source/Directory.Build.props

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Project>
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net6.0;net7.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;net8.0</TargetFrameworks>
     <ImplicitUsings>disable</ImplicitUsings>
     <Nullable>disable</Nullable>
     <Authors>Daniel Collingwood</Authors>

source/MailKitSimplified.Sender/Helpers/MailboxAddressHelper.cs

@@ -10,6 +10,21 @@ public static class MailboxAddressHelper
         private static readonly char[] _emailReplace = new char[] { '_', '.', '-' };
         private static readonly char[] _emailSeparator = new char[] { ';', ',', ' ', '&', '|' };
 
+#if NET5_0_OR_GREATER
+        /// <summary>
+        /// Truncated hexadecimal string with up to 16^32 combinations, used for logging.
+        /// </summary>
+        /// <param name="count">Base 16 exponent.</param>
+        /// <returns>Truncated hexadecimal string</returns>
+        public static string GenerateHexId(byte count = 32)
+        {
+            if (count > 32)
+                count = 32;
+            var uuid = Guid.NewGuid().ToString("n", null)[..count];
+            return uuid;
+        }
+#endif
+
         public static IEnumerable<MailboxAddress> ParseEmailContacts(string value)
         {
             IEnumerable<MailboxAddress> contacts = null;