Change CommandBehavior on ExecuteReaderAsync to match sync version

Dapper.Tests/Tests.Async.cs

@@ -734,6 +734,19 @@ select @@Name
                 ", new Product { Id = 1 })).Single();
             id.IsEqualTo(2);
         }
+
+        [Fact]
+        public async Task Issue1281_DataReaderOutOfOrderAsync()
+        {
+            using (var reader = await connection.ExecuteReaderAsync("Select 0, 1, 2"))
+            {
+                reader.Read().IsTrue();
+                reader.GetInt32(2).IsEqualTo(2);
+                reader.GetInt32(0).IsEqualTo(0);
+                reader.GetInt32(1).IsEqualTo(1);
+                reader.Read().IsFalse();
+            }
+        }
     }
 }
 #endif
\ No newline at end of file

Dapper/SqlMapper.Async.cs

@@ -721,7 +721,7 @@ private static async Task<IDataReader> ExecuteReaderImplAsync(IDbConnection cnn,
             {
                 cmd = (DbCommand)command.SetupCommand(cnn, paramReader);
                 if (wasClosed) await ((DbConnection)cnn).OpenAsync(command.CancellationToken).ConfigureAwait(false);
-                var reader = await cmd.ExecuteReaderAsync(GetBehavior(wasClosed, CommandBehavior.SequentialAccess), command.CancellationToken).ConfigureAwait(false);
+                var reader = await cmd.ExecuteReaderAsync(GetBehavior(wasClosed, CommandBehavior.Default), command.CancellationToken).ConfigureAwait(false);
                 wasClosed = false;
                 return reader;
             }