Function hyper_clientconn_options_http1_allow_multiline_headers 

#[unsafe(no_mangle)]
pub extern "C" fn hyper_clientconn_options_http1_allow_multiline_headers(
    opts: *mut hyper_clientconn_options,
    enabled: c_int,
) -> hyper_code

Available on crate feature ffi and hyper_unstable_ffi only.

Set whether HTTP/1 connections accept obsolete line folding for header values.

Newline codepoints (\r and \n) will be transformed to spaces when parsing.

Pass 0 to disable, 1 to enable.