### student API
// IN message: N/A
// - id: [Required], course ID
// - language: [Required], zh-CN, en-US. (Supported languages: https://docs.aws.amazon.com/translate/latest/dg/what-is-languages.html)
// - voice: [Required], Takumi. (Supported voices: https://docs.aws.amazon.com/zh_cn/polly/latest/dg/voicelist.html)
// OUT message:
// example1: {"type":"original","content":"哎，","isFinal":true}
// example2: {"type":"translated","content":"ねえ、"}
// example3: {"type":"lipSync","visemes":[{"time":12,"value":"t"},{"time":25,"value":"@"},{"time":200,"value":"sil"}]}
// example4: Binary data, PCM audio, 16K sampling rate, single channel, 16-bit depth, little endian
WEBSOCKET wss://{{$exampleServer}}}/ws/student?id=456&language=zh-CN&voice=Takumi