Module fallback 

Fallback strategies for network error handling

Provides comprehensive fallback mechanisms including:

• Alternative peer selection
• Relay fallback for NAT traversal
• Degraded mode operation
• Automatic retry with exponential backoff

Structs

FallbackConfig

Fallback strategy configuration

FallbackManager

Fallback manager for coordinating fallback strategies

RetryStats

Retry statistics

Enums

FallbackResult

Fallback result wrapper

FallbackStrategy

Fallback strategy for peer connections