channel.flow vs connection.blocked

[gomoripeti]

Does the RabbitMQ broker send channel.flow messages? Searching in the repo I only see that the amqp Erlang client supports receiving such message, and rabbit_reader also has clauses for it to receive from the client (though flow=false from the client is not supported any more)
But I cannot find any place where the server would send it to a client.
https://github.com/rabbitmq/rabbitmq-server/search?l=Erlang&q=%22channel.flow%22

Otoh the server does send connection.blocked messages, however the amqp Erlang client apparently does not itself do anything about it, but leaves it to the user (by register_blocked_handler).

Asking because the edoc of amqp_channel:call/3 says here that

This will return the atom 'blocked' if the server has
throttled the client for flow control reasons.

However the atom blocked is only returned if the server sent a channel.flow message and not in case of a connection.blocked message (unless I'm missing something).

What is the current status? Which message should be used by the server and handled by the client?

[michaelklishin]

channel.flow was a part of AMQP 0-8-0 and was quickly deprecated and dropped as not particularly effective.

connection.blocked and connection.unblocked were introduced in 2013 as AMQP 0-9-1 extensions on top of TCP-based back pressure mechanism.

[gomoripeti]

thanks for the historic insight