Question about multiple upstream->peer.free calls

[Mike Gagnon]

Hello,

I am developing a load-balancing module for nginx. I have noticed that
when a peer fails (say because the connection was reset by the peer)
the r->upstream->peer.free function is called multiple times on the
same peer connection: the first time with state == NGX_PEER_FAILED
set, and the second time with state == 0.

What is the purpose of calling peer.free multiple times? Is there a
recommended way to tell if a call to peer.free is the first call (for
that peer connection)? Or to tell if it is the last call (for that
peer connection)?

This issue is important for the correctness of my code.

Thanks!

Mike Gagnon