Add hooks that get called when the polling mechanism starts or ends.

src/telepathy/bot.cr

@@ -18,6 +18,8 @@ module Telepathy
             @last_update_id = nil
             @command_hooks = {} of String => Update, Array(String) -> Void
             @message_hooks = [] of Update -> Void
+            @poll_start_hooks = [] of -> Void
+            @poll_end_hooks = [] of -> Void
             @poll_channel = Channel(Int64?|Control).new
             @update_channel = Channel(Array(Update)|Control).new
             @poll_running = false
@@ -102,6 +104,14 @@ module Telepathy
             @message_hooks.push(block)
         end
 
+        def poll_start(&block: -> Void)
+            @poll_start_hooks.push(block);
+        end
+
+        def poll_end(&block: -> Void)
+            @poll_end_hooks.push(block);
+        end
+
         private def process_updates(updates)
             updates.each do |update|
                 if message = update.message
@@ -154,6 +164,7 @@ module Telepathy
                 @poll_running = true
                 spawn_workers
                 @poll_channel.send nil
+                @poll_start_hooks.each &.call
             end
         end
 
@@ -161,6 +172,7 @@ module Telepathy
             if @poll_running
                 @poll_running = false
                 @poll_channel.send Control::Done
+                @poll_end_hooks.each &.call
             end
         end
     end