SSL_CTX_set_psk_find_session_callback
SSL_CTX_set_psk_find_session_callback(ctx, psk_find_session_cb);
void SSL_CTX_set_psk_find_session_callback(SSL_CTX *ctx,
SSL_CTX_set_psk_find_session_callback(sctx, find_session_cb);
SSL_CTX_set_psk_find_session_callback(*sctx, find_session_cb);
SSL_CTX_set_psk_find_session_callback(sctx, find_session_cb);