func (r *ReadBuffer) FillFrom(ior io.Reader, n int) (int, error) {
	if len(r.buffer) < n {
		return 0, ErrEOF
	}

	r.err = nil
	r.remaining = r.buffer[:n]
	return io.ReadFull(ior, r.remaining)
}
func (r *ReadBuffer) FillFrom(ior io.Reader, n int) (int, error) {
	if len(r.buffer) < n {
		return 0, ErrEOF
	}

	r.err = nil
	r.remaining = r.buffer[:n]
	return io.ReadFull(ior, r.remaining)
}
func ( r * ReadBuffer ) FillFrom ( ior io . Reader , n int ) ( int , error ) { if len ( r . buffer ) < n { return 0 , ErrEOF } r . err = nil r . remaining = r . buffer [ : n ] return io . ReadFull ( ior , r . remaining ) }
// FillFrom fills the buffer from a reader
FillFrom fills the buffer from a reader