Add Utility.EmptyByteArray.

Author: bgrainger

src/MySqlConnector/Protocol/Payloads/AuthenticationMethodSwitchRequestPayload.cs

@@ -23,7 +23,7 @@ public static AuthenticationMethodSwitchRequestPayload Create(ReadOnlySpan<byte>
 				// if the packet is just the header byte (0xFE), it's an "Old Authentication Method Switch Request Packet"
 				// (possibly sent by a server that doesn't support CLIENT_PLUGIN_AUTH)
 				name = "mysql_old_password";
-				data = new byte[0];
+				data = Utility.EmptyByteArray;
 			}
 			else
 			{

src/MySqlConnector/Protocol/Payloads/EmptyPayload.cs

@@ -1,7 +1,9 @@
+using MySqlConnector.Utilities;
+
 namespace MySqlConnector.Protocol.Payloads
 {
 	internal static class EmptyPayload
 	{
-		public static PayloadData Instance { get; } = new PayloadData(new byte[0]);
+		public static PayloadData Instance { get; } = new PayloadData(Utility.EmptyByteArray);
 	}
 }

src/MySqlConnector/Protocol/Serialization/AuthenticationUtility.cs

@@ -2,13 +2,14 @@
 using System;
 using System.Security.Cryptography;
 using System.Text;
+using MySqlConnector.Utilities;
 
 namespace MySqlConnector.Protocol.Serialization
 {
 	internal static class AuthenticationUtility
 	{
 		public static byte[] CreateAuthenticationResponse(byte[] challenge, int offset, string password) =>
-			string.IsNullOrEmpty(password) ? s_emptyArray : HashPassword(challenge, offset, password);
+			string.IsNullOrEmpty(password) ? Utility.EmptyByteArray : HashPassword(challenge, offset, password);
 
 		/// <summary>
 		/// Hashes a password with the "Secure Password Authentication" method.
@@ -39,12 +40,10 @@ public static byte[] HashPassword(byte[] challenge, int offset, string password)
 			}
 		}
 
-		static readonly byte[] s_emptyArray = new byte[0];
-
 		public static byte[] CreateScrambleResponse(byte[] nonce, string password)
 		{
 			var scrambleResponse = string.IsNullOrEmpty(password)
-				? s_emptyArray
+				? Utility.EmptyByteArray
 				: HashPasswordWithNonce(nonce, password);
 
 			return scrambleResponse;

src/MySqlConnector/Utilities/Utility.cs

@@ -347,10 +347,13 @@ public static Task<T> TaskFromException<T>(Exception exception)
 			tcs.SetException(exception);
 			return tcs.Task;
 		}
+
+		public static byte[] EmptyByteArray { get; } = new byte[0];
 #else
 		public static Task CompletedTask => Task.CompletedTask;
 		public static Task TaskFromException(Exception exception) => Task.FromException(exception);
 		public static Task<T> TaskFromException<T>(Exception exception) => Task.FromException<T>(exception);
+		public static byte[] EmptyByteArray { get; } = Array.Empty<byte>();
 #endif
 
 #if !NETSTANDARD2_1 && !NETCOREAPP3_0