Metered Connection change notification failure on Windows 8

In Windows 8, the Network Cost awareness API lets applications query whether a connection is metered, enabling them to defer or throttle background data transfers to reduce charges on limited data plans. For low‑traffic workloads, this feature is critical to keep operational costs down. However, an unresolved behavior has been observed: when a network switches from metered to non‑metered (or vice versa) during an active session, running applications may not receive timely notifications. This can result in either unnecessary throttling or uncontrolled data usage, undermining the cost‑saving strategy.

Given the reliance on the metered flag, the key constraints are:

• Applications must detect the metered state change reliably.
• Windows 8’s event delivery for cost changes is inconsistent across network adapters.
• Legacy services may ignore the flag altogether.

To address this, we need to understand the underlying notification mechanism and any available workarounds.

1. Does Windows 8 provide a consistent event or callback for network cost changes?
2. Which API or system hook can reliably detect and respond to a metered state transition?
3. Are there documented workarounds or best practices to ensure low‑traffic workloads honor the metered flag?