Added missing async overrides for custom readers

Author: maca88

src/NHibernate/AdoNet/ResultSetWrapper.cs

@@ -2,6 +2,10 @@
 using System.Collections;
 using System.Data;
 using System.Data.Common;
+#if ASYNC
+using System.Threading;
+using System.Threading.Tasks;
+#endif
 
 namespace NHibernate.AdoNet
 {
@@ -47,6 +51,23 @@ public override bool Read()
 			return rs.Read();
 		}
 
+#if ASYNC
+		public override Task<bool> ReadAsync(CancellationToken cancellationToken)
+		{
+			return rs.ReadAsync(cancellationToken);
+		}
+
+		public override Task<bool> NextResultAsync(CancellationToken cancellationToken)
+		{
+			return rs.NextResultAsync(cancellationToken);
+		}
+
+		public override Task<bool> IsDBNullAsync(int ordinal, CancellationToken cancellationToken)
+		{
+			return rs.IsDBNullAsync(ordinal, cancellationToken);
+		}
+#endif
+
 		public override int Depth
 		{
 			get { return rs.Depth; }

src/NHibernate/Driver/BasicResultSetsCommand.cs

@@ -7,6 +7,10 @@
 using NHibernate.Engine;
 using NHibernate.SqlCommand;
 using NHibernate.SqlTypes;
+#if ASYNC
+using System.Threading;
+using System.Threading.Tasks;
+#endif
 
 namespace NHibernate.Driver
 {
@@ -273,6 +277,23 @@ public override bool Read()
 			return reader.Read();
 		}
 
+#if ASYNC
+		public override Task<bool> ReadAsync(CancellationToken cancellationToken)
+		{
+			return reader.ReadAsync(cancellationToken);
+		}
+
+		public override Task<bool> IsDBNullAsync(int ordinal, CancellationToken cancellationToken)
+		{
+			return reader.IsDBNullAsync(ordinal, cancellationToken);
+		}
+
+		public override Task<bool> NextResultAsync(CancellationToken cancellationToken)
+		{
+			return reader.NextResultAsync(cancellationToken);
+		}
+#endif
+
 		public override int Depth
 		{
 			get { return reader.Depth; }

src/NHibernate/Driver/NDataReader.cs

@@ -4,6 +4,10 @@
 using System.Data;
 using System.Data.Common;
 using NHibernate.Util;
+#if ASYNC
+using System.Threading;
+using System.Threading.Tasks;
+#endif
 
 namespace NHibernate.Driver
 {
@@ -161,6 +165,23 @@ public override bool Read()
 			return true;
 		}
 
+#if ASYNC
+		public override Task<bool> ReadAsync(CancellationToken cancellationToken)
+		{
+			return Task.FromResult(Read());
+		}
+
+		public override Task<bool> NextResultAsync(CancellationToken cancellationToken)
+		{
+			return Task.FromResult(NextResult());
+		}
+
+		public override Task<bool> IsDBNullAsync(int ordinal, CancellationToken cancellationToken)
+		{
+			return Task.FromResult(IsDBNull(ordinal));
+		}
+#endif
+
 		/// <summary></summary>
 		public override int Depth
 		{

src/NHibernate/Driver/NHybridDataReader.cs

@@ -2,6 +2,10 @@
 using System.Collections;
 using System.Data;
 using System.Data.Common;
+#if ASYNC
+using System.Threading;
+using System.Threading.Tasks;
+#endif
 
 namespace NHibernate.Driver
 {
@@ -126,6 +130,25 @@ public override bool Read()
 			return _isMidstream;
 		}
 
+#if ASYNC
+		public override async Task<bool> ReadAsync(CancellationToken cancellationToken)
+		{
+			_isMidstream = await _reader.ReadAsync(cancellationToken);
+			return _isMidstream;
+		}
+
+		public override Task<bool> NextResultAsync(CancellationToken cancellationToken)
+		{
+			_isMidstream = false;
+			return _reader.NextResultAsync(cancellationToken);
+		}
+
+		public override Task<bool> IsDBNullAsync(int ordinal, CancellationToken cancellationToken)
+		{
+			return _reader.IsDBNullAsync(ordinal, cancellationToken);
+		}
+#endif
+
 		/// <summary></summary>
 		public override int Depth
 		{