pub struct BIO {
    pub method: *mut BIO_METHOD,
    pub callback: Option<unsafe  extern "C" fn(*mut BIO, c_int, *const c_char, c_int, c_long, c_long) -> c_long>,
    pub cb_arg: *mut c_char,
    pub init: c_int,
    pub shutdown: c_int,
    pub flags: c_int,
    pub retry_reason: c_int,
    pub num: c_int,
    pub ptr: *mut c_void,
    pub next_bio: *mut BIO,
    pub prev_bio: *mut BIO,
    pub references: c_int,
    pub num_read: c_ulong,
    pub num_write: c_ulong,
    pub ex_data: CRYPTO_EX_DATA,
}Fields
                             method |  | 
                             callback |  | 
                             cb_arg |  | 
                             init |  | 
                             shutdown |  | 
                             flags |  | 
                             retry_reason |  | 
                             num |  | 
                             ptr |  | 
                             next_bio |  | 
                             prev_bio |  | 
                             references |  | 
                             num_read |  | 
                             num_write |  | 
                             ex_data |  |