Some more micro-optimization experiments.

experiments/Peregrine/Peregrine/Ado/PeregrineCommand.cs

@@ -12,8 +12,15 @@ namespace Peregrine.Ado
     public class PeregrineCommand : DbCommand
     {
         private readonly PGSession _session;
+        private readonly PeregrineDataReader _reader;
+        private readonly ReadBuffer _readBuffer;
 
-        public PeregrineCommand(PGSession session) => _session = session;
+        public PeregrineCommand(PGSession session)
+        {
+            _session = session;
+            _readBuffer = session.ReadBuffer;
+            _reader = new PeregrineDataReader(session.ReadBuffer);
+        }
 
         public Task PrepareAsync() => _session.PrepareAsync("p", CommandText);
 
@@ -21,26 +28,23 @@ namespace Peregrine.Ado
             CommandBehavior behavior, CancellationToken cancellationToken)
         {
             await _session.ExecuteAsync("p");
+            await _readBuffer.ReceiveAsync();
 
-            var readBuffer = _session.ReadBuffer;
+            var message = _readBuffer.ReadMessage();
 
-            await readBuffer.ReceiveAsync();
-
-            var message = readBuffer.ReadMessage();
-
-            switch (message.Type)
+            switch (message)
             {
                 case MessageType.BindComplete:
-                    return new PeregrineDataReader(readBuffer);
+                    return _reader;
 
                 case MessageType.ErrorResponse:
-                    throw new InvalidOperationException(readBuffer.ReadErrorMessage());
+                    throw new InvalidOperationException(_readBuffer.ReadErrorMessage());
 
                 default:
-                    throw new NotImplementedException(message.Type.ToString());
+                    throw new NotImplementedException(message.ToString());
             }
         }
-
+        
         public override int ExecuteNonQuery()
             => throw new NotImplementedException();
 

experiments/Peregrine/Peregrine/Ado/PeregrineDataReader.cs

@@ -23,12 +23,12 @@ namespace Peregrine.Ado
         {
             var message = _readBuffer.ReadMessage();
 
-            switch (message.Type)
+            switch (message)
             {
                 case MessageType.DataRow:
                 {
                     // Column count
-                    _readBuffer.ReadShort();
+                    _readBuffer.SkipShort();
 
                     return _trueResult;
                 }
@@ -40,7 +40,7 @@ namespace Peregrine.Ado
                     throw new InvalidOperationException(_readBuffer.ReadErrorMessage());
 
                 default:
-                    throw new NotImplementedException(message.Type.ToString());
+                    throw new NotImplementedException(message.ToString());
             }
         }
 

experiments/Peregrine/Peregrine/PGSession.cs

@@ -69,7 +69,7 @@ namespace Peregrine
 
             var message = _readBuffer.ReadMessage();
 
-            switch (message.Type)
+            switch (message)
             {
                 case MessageType.ParseComplete:
                     break;
@@ -78,7 +78,7 @@ namespace Peregrine
                     throw new InvalidOperationException(_readBuffer.ReadErrorMessage());
 
                 default:
-                    throw new NotImplementedException(message.Type.ToString());
+                    throw new NotImplementedException(message.ToString());
             }
         }
 
@@ -160,7 +160,7 @@ namespace Peregrine
 
             var message = _readBuffer.ReadMessage();
 
-            switch (message.Type)
+            switch (message)
             {
                 case MessageType.BindComplete:
                     goto read;
@@ -191,7 +191,7 @@ namespace Peregrine
                     throw new InvalidOperationException(_readBuffer.ReadErrorMessage());
 
                 default:
-                    throw new NotImplementedException(message.Type.ToString());
+                    throw new NotImplementedException(message.ToString());
             }
         }
 
@@ -219,7 +219,7 @@ namespace Peregrine
 
             var message = _readBuffer.ReadMessage();
 
-            switch (message.Type)
+            switch (message)
             {
                 case MessageType.AuthenticationRequest:
                 {
@@ -261,10 +261,10 @@ namespace Peregrine
                 case MessageType.EmptyQueryResponse:
                 case MessageType.ParameterStatus:
                 case MessageType.ReadyForQuery:
-                    throw new NotImplementedException($"Unhandled MessageType '{message.Type}'");
+                    throw new NotImplementedException($"Unhandled MessageType '{message}'");
 
                 default:
-                    throw new InvalidOperationException($"Unexpected MessageType '{message.Type}'");
+                    throw new InvalidOperationException($"Unexpected MessageType '{message}'");
             }
         }
 

experiments/Peregrine/Peregrine/ReadBuffer.cs

@@ -3,8 +3,6 @@
 
 using System;
 using System.Buffers.Binary;
-using System.IO;
-using System.Threading.Tasks;
 
 namespace Peregrine
 {
@@ -23,7 +21,17 @@ namespace Peregrine
             _awaitableSocket = awaitableSocket;
         }
 
-        internal (MessageType Type, int Length) ReadMessage()
+        internal MessageType ReadMessage()
+        {
+            var messageType = (MessageType)ReadByte();
+
+            // Skip length
+            _position += sizeof(int);
+
+            return messageType;
+        }
+
+        internal (MessageType Type, int Length) ReadMessageWithLength()
         {
             var messageType = (MessageType)ReadByte();
             var length = ReadInt() - 4;
@@ -68,6 +76,11 @@ namespace Peregrine
             return bs;
         }
 
+        public void SkipShort()
+        {
+            _position += sizeof(short);
+        }
+
         public short ReadShort()
         {
             var result = BinaryPrimitives.ReadInt16BigEndian(_buffer.Span.Slice(_position, 2));