title: Dapper QueryMultipleAsync ignoring parameters
body: <p>I'm trying to use Dapper QueryMultipleAsync. When I use a testing query without parameters, it works as expected, but when I try to use parameters, the execution hangs indefenitely.</p>
  
  <p>This is the code I'm trying to execute:</p>
  
  <pre><code>public async Task&lt;IHttpActionResult&gt; Get (string cnpj)
  {
      string cs = ConfigurationManager.ConnectionStrings["connectionStringBaseReceita"].ConnectionString;
  
      using(var conn = new SqlConnection(cs))
      {
          string sql = @"
          SELECT * FROM Empresas WHERE Cnpj = @cnpj ;
          SELECT * FROM QuadroSocietario WHERE Cnpj = @cnpj ;
          SELECT * FROM EmpresasCnaesSecundarios WHERE Cnpj = @cnpj ;
          ";
  
          var multi = await conn.QueryMultipleAsync(sql, new { cnpj }); //line where the code hangs
          var empresa = await multi.ReadSingleAsync&lt;EmpresaModel&gt;();
          empresa.QuadrosSocietarios = await multi.ReadAsync&lt;QuadroSocietarioModel&gt;();
          empresa.CnaesSecundarios = await multi.ReadAsync&lt;CnaeSecundarioModel&gt;();
  
          return Content(HttpStatusCode.OK, empresa);
      }
  }
  </code></pre>
  
  <p>but if I use a testing query like this without parameters, everythings works:</p>
  
  <pre><code>string sql = @"
  SELECT * FROM Empresas WHERE Cnpj = '08078861000102';
  SELECT * FROM QuadroSocietario WHERE Cnpj = '08078861000102';
  SELECT * FROM EmpresasCnaesSecundarios WHERE Cnpj = '08078861000102';
  ";
  </code></pre>
  
  <p>in the line where I call QueryMultipleAsync I tryed to specify the parameters in the following ways:</p>
  
  <ul>
  <li><code>conn.QueryMultipleAsync(sql, new { cnpj });</code></li>
  <li><code>conn.QueryMultipleAsync(sql, new { cnpj = cnpj });</code></li>
  <li><code>conn.QueryMultipleAsync(sql, new { @cnpj });</code></li>
  <li><code>conn.QueryMultipleAsync(sql, new { @cnpj = cnpj });</code></li>
  </ul>
  
  <p>I also tryed to specify '?' in the query to pass a not named parameter: </p>
  
  <pre><code>string sql = @"
  SELECT * FROM Empresas WHERE Cnpj = ? ;
  SELECT * FROM QuadroSocietario WHERE Cnpj = ? ;
  SELECT * FROM EmpresasCnaesSecundarios WHERE Cnpj = ? ;
  ";
  </code></pre>
  
  <p>but this fired a <code>Incorrect syntax near '?'</code> in the database.</p>