### Question:
B2IoUtils { @SuppressWarnings("UnusedReturnValue") public static long copy(InputStream in, OutputStream out) throws IOException { return copyGuts(in, out, new byte[4 * 1024]); }  @SuppressWarnings("UnusedReturnValue") static long copy(InputStream in,
                            OutputStream out); static void closeQuietly(Closeable closeable); static void readToEnd(InputStream in);  }### Answer:
@Test public void testCopy() throws IOException { checkCopy(makeBytes(0)); checkCopy(makeBytes(100)); checkCopy(makeBytes((4 * 1024) + 123)); }