Function try_tool_call_parse_stream 

pub async fn try_tool_call_parse_stream(
    message: &str,
    parser_str: Option<&str>,
) -> Result<(Vec<ChatCompletionMessageToolCallChunk>, Option<String>)>

Try parsing a string as a structured tool call, for streaming (delta) usage.

If successful, returns a ChatCompletionMessageToolCallChunk.