Function ble_gattc_read_mult_var 

pub unsafe extern "C" fn ble_gattc_read_mult_var(
    conn_handle: u16,
    handles: *const u16,
    num_handles: u8,
    cb: Option<unsafe extern "C" fn(u16, *const ble_gatt_error, *mut ble_gatt_attr, u8, *mut c_void) -> i32>,
    cb_arg: *mut c_void,
) -> i32