Function wait_for_process_ready 

pub fn wait_for_process_ready<F>(
    target: Address,
    request_body: Vec<u8>,
    timeout_s: u64,
    retry_delay_s: u64,
    classify: F,
    treat_unknown_as_ready: bool,
    max_attempts: Option<u32>,
)
where
    F: FnMut(&[u8]) -> WaitClassification,

Poll a target process until it reports ready while blocking.

• target: process address to poll (e.g., hypermap-cacher).
• request_body: request payload to send each attempt.
• timeout_s: per-request timeout in seconds.
• retry_delay_s: delay between attempts when not ready or on error.
• classify: function to classify the response body.
• treat_unknown_as_ready: if true, any non-starting response is treated as ready.
• max_attempts: number of attempts before continuing without a ready response.