Currently, `lrmd_send_command()` with `expect_reply` set to `TRUE`, and `lrmd_handshake()`, call `lrmd_send_xml()` with a non-NULL `reply`. That causes it to call `crm_ipc_send()` or `lrmd_tls_send_recv()` with a blocking timeout.
We want the commands to be asynchronous for internal callers, so they get a callback when the reply is received (or after the timeout).
`lrmd_send_command()` is currently used by most of the `lrmd_t` methods. The interfaces will need to be left as-is since they are public. If possible, we can set some `lrmd_t` flag for internal connections and use async when that's set, otherwise we may need a duplicate set of async methods (which can be regular internal functions rather than part of `lrmd_api_operations_t`).