Add synchronize after async transfer
Add synchronize after async transfer

keisuke-umezawa/chainer,niboshi/chainer,jnishi/chainer,wkentaro/chainer,okuta/chainer,okuta/chainer,keisuke-umezawa/chainer,ktnyt/chainer,hvy/chainer,pfnet/chainer,wkentaro/chainer,hvy/chainer,chainer/chainer,chainer/chainer,hvy/chainer,keisuke-umezawa/chainer,ktnyt/chainer,tkerola/chainer,keisuke-umezawa/chainer,niboshi/chainer,okuta/chainer,ktnyt/chainer,wkentaro/chainer,ktnyt/chainer,chainer/chainer,niboshi/chainer,okuta/chainer,jnishi/chainer,wkentaro/chainer,chainer/chainer,jnishi/chainer,jnishi/chainer,hvy/chainer,niboshi/chainer