Struct SynthesizeRequest 

pub struct SynthesizeRequest<'a> {
    pub text: &'a str,
    pub voice: Option<&'a str>,
    pub instruction: Option<&'a str>,
    pub language: Option<&'a str>,
    pub speed: Option<f32>,
}

A TTS synthesis request.

Backend-agnostic parameters that describe what to synthesize. Each backend interprets voice, instruction, and language according to its own capabilities; unsupported fields are silently ignored.

Fields

text: &'a str

Text to synthesize.

voice: Option<&'a str>

Voice identifier (backend-specific).

Used by backends with a fixed speaker catalog:

• Edge-TTS: "zh-CN-XiaoxiaoNeural", "zh-CN-YunxiNeural", …
• Kokoro: "af_heart", "zf_xiaobei", …

None uses the backend’s default voice.

instruction: Option<&'a str>

Free-form voice instruction / style prompt.

Used by instruction-following backends (e.g. Qwen3-TTS VoiceDesign). The text describes how the model should speak:

"Speak in a calm, professional tone."
"Narrate with warmth and a gentle pace."
"Respond with high energy and enthusiasm!"

None lets the backend use its default voice character.

language: Option<&'a str>

Language / locale code.

E.g. "zh", "en", "ja". None uses the backend’s default or auto-detects.

speed: Option<f32>

Speed multiplier. 1.0 is normal speed.

Values below 1.0 slow down, above 1.0 speed up. Not all backends support this; unsupported values are ignored.

Implementations

impl<'a> SynthesizeRequest<'a>

pub fn new(text: &'a str) -> Self

Create a minimal request with just text.

pub fn with_voice(self, voice: &'a str) -> Self

Set the voice identifier.

pub fn with_instruction(self, instruction: &'a str) -> Self

Set the voice instruction / style prompt.

pub fn with_language(self, language: &'a str) -> Self

Set the language.

pub fn with_speed(self, speed: f32) -> Self

Set the speed multiplier.

Trait Implementations

impl<'a> Clone for SynthesizeRequest<'a>

fn clone(&self) -> SynthesizeRequest<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Debug for SynthesizeRequest<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.