Function encode_part_head 

pub fn encode_part_head(
    boundary: &Boundary,
    first: bool,
    name: &str,
    filename: Option<&str>,
    content_type: Option<&str>,
    out: &mut [u8],
) -> Result<usize, FormError>

Writes one part’s head into out without allocating: the delimiter (with its leading CRLF unless first), the Content-Disposition line with browser escaping, the optional Content-Type line, and the blank line. Returns the bytes written.

After the last part’s data the caller writes the close delimiter: Boundary::delimiter followed by --\r\n; for a body with no parts, --, the boundary, and --\r\n.

Errors

BufferTooSmall { needed } (nothing is written); Syntax { EmptyName | ControlInHeader | AmbiguousQuote | InvalidContentType }.

Examples

let b = form_net::Boundary::new(b"X")?;
let mut out = [0u8; 128];
let n = form_net::encode_part_head(&b, true, "a\"b", None, None, &mut out)?;
assert_eq!(&out[..n], b"--X\r\nContent-Disposition: form-data; name=\"a%22b\"\r\n\r\n");