WithEncoding.pm.patch

diff --git a/lib/Plack/Request/WithEncoding.pm b/lib/Plack/Request/WithEncoding.pm
index 45d3d3f..aa8f36b 100644
--- a/lib/Plack/Request/WithEncoding.pm
+++ b/lib/Plack/Request/WithEncoding.pm
@@ -81,11 +81,34 @@ sub _decode_parameters {
     my @flatten = $stuff->flatten;
     my @decoded;
     while ( my ($k, $v) = splice @flatten, 0, 2 ) {
-        push @decoded, $encoding->decode($k), $encoding->decode($v);
+        push @decoded, $self->__decode($encoding, $k), $self->__decode($encoding, $v);
     }
     return Hash::MultiValue->new(@decoded);
 }
_
+sub __decode {
+    my ($self, $encoding, $data) = @_;
+
+    if (ref $data eq "ARRAY") {
+        my @result;
+        for my $d (@$data) {
+            push @result, $self->__decode($encoding, $d);
+        }
+
+        return \@result;
+    }
+    elsif (ref $data eq "HASH") {
+        my %result;
+        while (my ($k, $v) = each %$data) {
+            $result{$self->__decode($encoding, $k)} = $self->__decode($encoding, $v);
+        }
+
+        return \%result;
+    }
+
+    return $encoding->decode($data);
+}
+
 1;
 __END__