Accept symbol, proc, and nil arguments for broadcasts_refreshes

[mrrooijen]

Currently, broadcasts_refreshes only accepts values in the form of a string or nil, where explicitly passing nil bypasses broadcasting but still triggers the after_create_commit callback.

This change allows you to pass a symbol (method name to call) or a proc to evaluate to broadcasts_refreshes to produce a stream name dynamically at the instance level after_create_commit.

This allows us to, for example, specify a parent (Board) to broadcast refreshes to on create, while broadcasting to itself (Column) on update and destroy:

class Column < ApplicationRecord
  belongs_to :board
  broadcasts_refreshes :board
end

Listen for new Column creations for @board:

<%= turbo_stream_from @board %> 

Listen for updates and deletion of existing @column:

<%= turbo_stream_from @column %> 

This changes also disables the entire after_create_commit hook if nil is passed in explicitly, rather than allowing it to run without broadcasting anything.