Function fz_new_buffer_from_data 

pub unsafe extern "C" fn fz_new_buffer_from_data(
    ctx: *mut fz_context,
    data: *mut c_uchar,
    size: usize,
) -> *mut fz_buffer

Create a new buffer with existing data.

data: Pointer to existing data.
size: Size of existing data.

Takes ownership of data. Does not make a copy. Calls fz_free on
the data when the buffer is deallocated. Do not use ‘data’ after
passing to this function.

Returns pointer to new buffer. Throws exception on allocation
failure.