* and a fixed number of values. Each key must match the regex `[a-z0-9_-]{1,64}`. Values are byte
 * sequences, accessible as streams or files. Each value must be between `0` and `Int.MAX_VALUE`
 * bytes in length.
 *
 * The cache stores its data in a directory on the filesystem. This directory must be exclusive to

   * @return the number of characters copied
   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue
  public static long copy(Readable from, Appendable to) throws IOException {
    // The most common case is that from is a Reader (like InputStreamReader or StringReader) so
    // take advantage of that.
    if (from instanceof Reader) {
      // optimize for common output types which are optimized to deal with char[]

			// being deleted by most users, but you can still grant some users
			// permission to alter the retention settings or delete the object
			// if necessary. You can also use governance mode to test retention-period
			// settings before creating a compliance-mode retention period.
			// To override or remove governance-mode retention settings, a
			// user must have the s3:BypassGovernanceRetention permission

   *
   * @param key the non-null key whose value should be loaded
   * @param oldValue the non-null old value corresponding to {@code key}
   * @return the future new value associated with {@code key}; <b>must not be null, must not return
   *     null</b>
   * @throws Exception if unable to reload the result
   * @throws InterruptedException if this method is interrupted. {@code InterruptedException} is

	}
	fmt.Fprintf(os.Stderr, "%s:%d: %s", in.File(), in.Line(), fmt.Sprintln(args...))
	os.Exit(1)
}

// expectText is like Error but adds "got XXX" where XXX is a quoted representation of the most recent token.
func (in *Input) expectText(args ...interface{}) {
	in.Error(append(args, "; got", strconv.Quote(in.Stack.Text()))...)
}

// enabled reports whether the input is enabled by an ifdef, or is at the top level.

      setException(t);
      return;
    } finally {
      function = null;
    }

    /*
     * If set()/setValue() throws an Error, we let it propagate. Why? The most likely Error is a
     * StackOverflowError (from deep transform(..., directExecutor()) nesting), and calling
     * setException(stackOverflowError) would fail:
     *

      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>

  <!-- servers
   | This is a list of authentication profiles, keyed by the server-id used within the system.
   | Authentication profiles can be used whenever maven must make a connection to a remote server.
   |-->
  <servers>

    logger.error("Class not found: " + className, e);
}
```

## 🏗️ Architecture & Design Patterns

### Core Design Principles
CoreLib follows a **utility-class pattern** where most functionality is exposed through static methods:

- **Assertion-based validation** - All methods validate inputs using `AssertionUtil.assertArgumentNotNull()` and `AssertionUtil.assertArgumentNotEmpty()`

                    this.addresses = this.ctx.getNameServiceClient().getAllByName(host, true);
                } else {
                    this.addresses = this.ctx.getNameServiceClient().getAllByName(host, false);
                }
            } catch (final UnknownHostException e) {
                throw new CIFSException("Failed to lookup address for name " + host, e);
            }
        }

        return getNextAddress();

   * MoreExecutors#directExecutor}. Otherwise, avoid it: See the warnings on the docs for {@code
   * directExecutor}.
   *
   * <p>This is the most general listener interface. For common operations performed using
   * listeners, see {@link Futures}. For a simplified but general listener interface, see {@link
   * Futures#addCallback addCallback()}.
   *