Use more UTF-8 literals.

Author: bgrainger

src/MySqlConnector/MySqlParameter.cs

@@ -338,7 +338,7 @@ internal void AppendSqlString(ByteBufferWriter writer, StatementPreparerOptions
 			if (mySqlDateTimeValue.IsValidDateTime)
 				writer.Write("timestamp('{0:yyyy'-'MM'-'dd' 'HH':'mm':'ss'.'ffffff}')".FormatInvariant(mySqlDateTimeValue.GetDateTime()));
 			else
-				writer.Write("timestamp('0000-00-00')");
+				writer.Write("timestamp('0000-00-00')"u8);
 		}
 #if NET6_0_OR_GREATER
 		else if (Value is DateOnly dateOnlyValue)
@@ -363,13 +363,13 @@ internal void AppendSqlString(ByteBufferWriter writer, StatementPreparerOptions
 #if NET6_0_OR_GREATER
 		else if (Value is TimeOnly timeOnlyValue)
 		{
-			writer.Write("time '");
+			writer.Write("time '"u8);
 			writer.Write("{0:HH':'mm':'ss'.'ffffff}'".FormatInvariant(timeOnlyValue));
 		}
 #endif
 		else if (Value is TimeSpan ts)
 		{
-			writer.Write("time '");
+			writer.Write("time '"u8);
 			if (ts.Ticks < 0)
 			{
 				writer.Write((byte) '-');

src/MySqlConnector/Protocol/Payloads/ChangeUserPayload.cs

@@ -15,7 +15,7 @@ public static PayloadData Create(string user, ReadOnlySpan<byte> authResponse, s
 		writer.WriteNullTerminatedString(schemaName ?? "");
 		writer.Write((byte) characterSet);
 		writer.Write((byte) 0);
-		writer.WriteNullTerminatedString("mysql_native_password");
+		writer.Write("mysql_native_password\0"u8);
 		if (connectionAttributes is not null)
 			writer.Write(connectionAttributes);
 

src/MySqlConnector/Protocol/Payloads/HandshakeResponse41Payload.cs

@@ -64,7 +64,7 @@ public static PayloadData Create(InitialHandshakePayload handshake, ConnectionSe
 			writer.WriteNullTerminatedString(cs.Database);
 
 		if ((handshake.ProtocolCapabilities & ProtocolCapabilities.PluginAuth) != 0)
-			writer.WriteNullTerminatedString("mysql_native_password");
+			writer.Write("mysql_native_password\0"u8);
 
 		if (connectionAttributes is not null)
 			writer.Write(connectionAttributes);