### Question:
DirectCharSink extends AbstractCharSink implements CharSequence, Closeable, Mutable { private void resize(int cap) { long temp = Unsafe.malloc(cap); int len = (int) (lo - ptr); Unsafe.getUnsafe().copyMemory(ptr, temp, len); Unsafe.free(ptr, capacity); this.ptr = temp; this.capacity = cap; this.lo = ptr + len; this.hi = ptr + cap; } DirectCharSink(int capacity); @Override void clear(); @Override void close(); @Override int length(); @Override char charAt(int index); @Override CharSequence subSequence(int start, int end); @Override CharSink put(CharSequence cs); @Override CharSink put(char[] chars, int start, int len); @Override CharSink put(char c); @NotNull @Override String toString();  }### Answer:
@Test public void testResize() { final String expected = "string 0\n" + "string 1\n" + "string 2\n" + "string 3\n" + "string 4\n" + "string 5\n" + "string 6\n" + "string 7\n" + "string 8\n" + "string 9\n" + "string 10\n" + "string 11\n" + "string 12\n" + "string 13\n" + "string 14\n" + "string 15\n" + "string 16\n" + "string 17\n" + "string 18\n" + "string 19\n" + "string 20\n" + "string 21\n" + "string 22\n" + "string 23\n" + "string 24\n" + "string 25\n" + "string 26\n" + "string 27\n" + "string 28\n" + "string 29\n"; try (DirectCharSink sink = new DirectCharSink(16)) { for (int i = 0; i < 30; i++) { sink.put("string ").put(i).put('\n'); } TestUtils.assertEquals(expected, sink); sink.clear(); for (int i = 0; i < 30; i++) { sink.put("string ").put(i).put('\n'); } TestUtils.assertEquals(expected, sink); } }