SessionPlugin<CTX extends Context, TSession> class

A comprehensive session management plugin.

This plugin provides persistent session storage for bots, allowing them to remember data across updates. Sessions are stored per chat and automatically loaded/saved with each update.

Example usage:

// Basic session with Map storage
bot.plugin(SessionPlugin<Context, Map<String, dynamic>>(
  initial: () => {'count': 0, 'name': ''},
));

// Custom session key generation
bot.plugin(SessionPlugin<Context, UserSession>(
  initial: () => UserSession(),
  getSessionKey: (ctx) => 'user_${ctx.from?.id ?? 0}',
));

// Usage in handlers
bot.command('count', (ctx) async {
  final session = ctx.session as Map<String, dynamic>;
  session['count'] = (session['count'] as int) + 1;
  await ctx.reply('Count: ${session['count']}');
});