title: Masking input from Multi-head attention layer
body: <p>I am trying to use the Keras masking layer to mask my input from a self made transformer, my code contains a MultiHeadAttention layer: and I looked at its code <a href="https://github.com/keras-team/keras/blob/v2.8.0/keras/layers/multi_head_attention.py" rel="nofollow noreferrer">here</a> and it seems it lacks the <strong>supports_masking</strong> argument like I read it should have. However it does not throw an exception when I use the masking layer either...so I am not sure, does MHA support masking or not? and does it propagate the mask further too?</p>