new_size = pipe_buf.length * 2;
            if( len > ( new_size - used )) {
                new_size = len + used;
            }
            tmp = pipe_buf;
            pipe_buf = new byte[new_size];
            i = tmp.length - beg_idx;
            if( used > i ) { /* 2 chunks */
                System.arraycopy( tmp, beg_idx, pipe_buf, 0, i );
                System.arraycopy( tmp, 0, pipe_buf, i, used - i ); 

			}
			defer pr1.Close()
			defer pw1.Close()

			pr2, pw2, err := Pipe()
			if err != nil {
				t.Fatal(err)
			}
			defer pr2.Close()
			defer pw2.Close()

			// The pipe is empty, and PIPE_BUF is large enough
			// for this, by (POSIX) definition, so there is no
			// need for an additional goroutine.
			data := []byte("hello")
			if _, err := pw1.Write(data); err != nil {
				t.Fatal(err)
			}