Module subscription 

Generic subscription state tracking for WebSocket clients.

This module provides a robust subscription tracker that maintains confirmed and pending subscription states with reference counting support. It follows a proven pattern used in production.

Key Features

• Three-state tracking: confirmed, pending_subscribe, pending_unsubscribe.
• Reference counting: Prevents duplicate subscribe/unsubscribe messages.
• Reconnection support: all_topics() returns topics to resubscribe after reconnect.
• Configurable delimiter: Supports different topic formats (. or : etc.).

Topic Format

Topics are strings in the format channel{delimiter}symbol:

• Dot delimiter: tickers.BTCUSDT
• Colon delimiter: trades:BTC-USDT

Channels without symbols are also supported (e.g., execution for all instruments).

Structs

SubscriptionState

Generic subscription state tracker for WebSocket connections.

Functions

split_topic

Splits a topic into channel and optional symbol using the specified delimiter.