naming consistency and other feedback

Author: twsouthwick

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObjectManaged.cs

@@ -94,7 +94,7 @@ internal override void CreatePhysicalSNIHandle(
             string hostNameInCertificate,
             string serverCertificateFilename)
         {
-            SNIHandle? sessionHandle = SNIProxy.CreateConnectionHandle(serverName, timeout, out instanceName, ref spn, serverSPN,
+            SNIHandle? sessionHandle = SNIProxy.CreateConnectionHandle(serverName, timeout, out instanceName, ref spns, serverSPN,
                 flushCache, async, parallel, isIntegratedSecurity, iPAddressPreference, cachedFQDN, ref pendingDNSInfo, tlsFirst,
                 hostNameInCertificate, serverCertificateFilename);
 

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObjectNative.cs

@@ -178,7 +178,7 @@ internal override void CreatePhysicalSNIHandle(
 
             _sessionHandle = new SNIHandle(myInfo, serverName, ref serverSPN, timeout.MillisecondsRemainingInt, out instanceName,
                 flushCache, !async, fParallel, ipPreference, cachedDNSInfo, hostNameInCertificate);
-            spn = new[] { serverSPN.TrimEnd() };
+            spns = new[] { serverSPN.TrimEnd() };
         }
 
         protected override uint SNIPacketGetData(PacketHandle packet, byte[] _inBuff, ref uint dataSize)

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/BufferWriterExtensions.cs

@@ -1,4 +1,5 @@
-using System.Buffers;
+using System;
+using System.Buffers;
 using System.Text;
 
 namespace Microsoft.Data.SqlClient
@@ -12,9 +13,9 @@ internal static long GetBytes(this Encoding encoding, string str, IBufferWriter<
 
             try
             {
-                encoding.GetBytes(str, 0, str.Length, array, 0);
-                bufferWriter.Write(array);
-                return count;
+                var length = encoding.GetBytes(str, 0, str.Length, array, 0);
+                bufferWriter.Write(array.AsSpan(0, length));
+                return length;
             }
             finally
             {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SSPI/NativeSSPIContextProvider.cs

@@ -62,7 +62,7 @@ protected override void GenerateSspiClientContext(ReadOnlySpan<byte> incomingBlo
             var sendLength = s_maxSSPILength;
             var outBuff = outgoingBlobWriter.GetSpan((int)sendLength);
 
-            if (0 != SniNativeWrapper.SNISecGenClientContext(handle, incomingBlob, outBuff, ref sendLength, serverSpn[0]))
+            if (0 != SniNativeWrapper.SNISecGenClientContext(handle, incomingBlob, outBuff, ref sendLength, serverSpns[0]))
             {
                 throw new InvalidOperationException(SQLMessage.SSPIGenerateError());
             }

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SSPI/NegotiateSSPIContextProvider.cs

@@ -1,7 +1,6 @@
 #if NET
 
 using System;
-using System.Text;
 using System.Net.Security;
 using System.Buffers;
 
@@ -12,14 +11,14 @@ namespace Microsoft.Data.SqlClient
     internal sealed class NegotiateSSPIContextProvider : SSPIContextProvider
     {
         private NegotiateAuthentication? _negotiateAuth = null;
-         
-        protected override void GenerateSspiClientContext(ReadOnlySpan<byte> incomingBlob, IBufferWriter<byte> outgoingBlobWriter, ReadOnlySpan<string> serverNames)
+
+        protected override void GenerateSspiClientContext(ReadOnlySpan<byte> incomingBlob, IBufferWriter<byte> outgoingBlobWriter, ReadOnlySpan<string> serverSpns)
         {
             NegotiateAuthenticationStatusCode statusCode = NegotiateAuthenticationStatusCode.UnknownCredentials;
 
-            for (int i = 0; i < serverNames.Length; i++)
+            for (int i = 0; i < serverSpns.Length; i++)
             {
-                _negotiateAuth ??= new(new NegotiateAuthenticationClientOptions { Package = "Negotiate", TargetName = serverNames[i] });
+                _negotiateAuth ??= new(new NegotiateAuthenticationClientOptions { Package = "Negotiate", TargetName = serverSpns[i] });
                 var sendBuff = _negotiateAuth.GetOutgoingBlob(incomingBlob, out statusCode)!;
 
                 // Log session id, status code and the actual SPN used in the negotiation

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SSPI/SSPIContextProvider.cs

@@ -37,7 +37,7 @@ internal void SSPIData(ReadOnlySpan<byte> receivedBuff, IBufferWriter<byte> outg
             {
                 try
                 {
-                    GenerateSspiClientContext(receivedBuff, outgoingBlobWriter, serverSpn);
+                    GenerateSspiClientContext(receivedBuff, outgoingBlobWriter, serverSpns);
                 }
                 catch (Exception e)
                 {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlObjectPool.cs

@@ -3,9 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Buffers;
 using System.Diagnostics;
-using System.Text;
 using System.Threading;
 
 namespace Microsoft.Data.SqlClient