TwiML `<ConversationRelay>` emits 4 attributes in lowercase instead of documented camelCase

Summary

ConversationRelay serializes four attributes in all-lowercase, but the ConversationRelay TwiML docs document them in camelCase. XML attributes are case-sensitive, so these are silently ignored by the TwiML parser — the setting appears to apply but has no effect, with no error surfaced.

Affected attributes

src/main/java/com/twilio/twiml/voice/ConversationRelay.java:

Every other attribute in the same class is correct camelCase (ttsLanguage, transcriptionProvider, speechModel, interruptSensitivity, …), and Gather.java:261 correctly emits speechTimeout for the same concept.

Reproduction

String xml = new VoiceResponse.Builder()
        .connect(new Connect.Builder()
                .conversationRelay(new ConversationRelay.Builder()
                        .url("wss://example.com/ws")
                        .speechtimeout("2000")
                        .build())
                .build())
        .build()
        .toXml();

Produces <ConversationRelay url="wss://example.com/ws" speechtimeout="2000"/>; expected speechTimeout="2000".

Impact

Observed in production: a speechtimeout="2000" setting had no effect on end-of-speech reporting. Measured delay from end of caller speech to the prompt WebSocket frame across four utterances in one call was 0.45s / 0.61s / 0.95s / 1.17; all well under the configured 2000ms, consistent with the attribute being dropped and the default auto applying.

The failure is silent, which makes it costly: the config looks applied in code review and in the generated TwiML, and only careful timing analysis reveals it isn't.

Start in src/main/java/com/twilio/twiml/voice/ConversationRelay.java at lines 165, 168, 171, and 174, then run the provided VoiceResponse reproduction to inspect the generated XML. Update the four emitted attribute names to match the documented camelCase forms and verify the output uses backgroundNoiseReduction, speechTimeout, deepgramSmartFormat, and ignoreBackchannel.