Send assumes connection is established for channel.

[cmeiklejohn]

Right now, in do_send_message in the default peer service manager, it's assumed that if a node is connected, that a connection is open for the channel.

Options:

• Since the default channel is always the first established, use the default channel for the message if a message specific channel has not been established yet; or
• Buffer the message until the channel for those types of messages is established.

Thoughts? @slfritchie @seancribbs @tsloughter

[seancribbs]

What sorts of guarantees does a channel provide? If there's an expectation of linearizability of a sequence of messages from the same origin process over the channel, I would not take option A. If the default channel is overloaded (or buffering, or changing window size, etc), you could have messages delivered out of order.

[aramallo]

Partisan currently uses option A, ie fallbacks to the default channel connection.

In v5.0.0-beta we have fast connection status checks by channel, so we can use this to implement option B or any other option.

I would like to have this to be managed by user prefs ie decision to fallback in default channel or to queue messages by channel.