Read the REST Response Body in Chunks

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Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

let rest = chilkat::Rest::new();
let b_tls = true;
let b_auto_reconnect = true;
if rest.connect("example.com", 443, b_tls, b_auto_reconnect).is_err() {
    println!("{}", rest.last_error_text());
    return;
}

if rest.send_req_no_body("GET", "/api/largefile").is_err() {
    println!("{}", rest.last_error_text());
    return;
}

let status_code = rest.read_response_header();
if status_code < 0 {
    println!("{}", rest.last_error_text());
    return;
}

// Check for the expected success status code.  If the response is not 200, the body is likely
// error text formatted as JSON, XML, or HTML rather than the expected content.  In that case read
// the body as text, report it, and return.
if status_code != 200 {
    let sb_error = chilkat::StringBuilder::new();
    if rest.read_resp_sb(&sb_error).is_err() {
        println!("{}", rest.last_error_text());
        return;
    }

    println!("Request failed with status code {}", status_code);
    println!("{}", sb_error.get_as_string().unwrap_or_default());
    return;
}

// The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
// Each call waits until at least the requested number of bytes is available, unless the response
// ends first.  A return value of 0 means the final bytes were returned and the body is complete;
// -1 indicates a read failure.
let bd_body = chilkat::BinData::new();
let mut chunk_result = rest.read_resp_chunk_bd(8192, &bd_body);
while chunk_result > 0 {
    chunk_result = rest.read_resp_chunk_bd(8192, &bd_body);
}

if chunk_result < 0 {
    println!("{}", rest.last_error_text());
    return;
}

println!("Received {} bytes.", bd_body.num_bytes());