Struct SttFallbackChain 

pub struct SttFallbackChain { /* private fields */ }

Fallback chain for STT: local -> cloud on failure or low confidence.

Decision logic:

1. Try local engine.
2. If local succeeds with confidence >= threshold: return local result.
3. If local succeeds with low confidence: try cloud, return whichever has higher confidence. On cloud error, return the local result.
4. If local fails: try cloud. On cloud error too, propagate the local error (unless no cloud provider is configured).

Implementations

impl SttFallbackChain

pub fn new(local: Box<dyn LocalSttEngine>) -> Self

Create a new chain with only a local engine.

pub fn with_cloud(self, provider: Box<dyn CloudSttProvider>) -> Self

Add a cloud provider for fallback.

pub fn with_confidence_threshold(self, threshold: f32) -> Self

Override the confidence threshold (default: 0.60).

pub async fn transcribe( &self, audio_data: &[u8], mime_type: &str, language: Option<&str>, ) -> Result<SttFallbackResult, PluginError>

Transcribe audio, falling back to cloud if local fails or confidence is below the threshold.