if atEOF && len(data) == 0 {
		return 0, nil, nil
	}

	// Fast path 1: ASCII.
	if data[0] < utf8.RuneSelf {
		return 1, data[0:1], nil
	}

	// Fast path 2: Correct UTF-8 decode without error.
	_, width := utf8.DecodeRune(data)
	if width > 1 {
		// It's a valid encoding. Width cannot be one for a correctly encoded
		// non-ASCII rune.
		return width, data[0:width], nil
	}

    checkArgument(!token.isEmpty());
    return Ascii.toLowerCase(token);
  }

  private static String normalizeParameterValue(String attribute, String value) {
    checkNotNull(value); // for GWT
    checkArgument(ascii().matchesAllOf(value), "parameter values must be ASCII: %s", value);
    return attribute.equals(CHARSET_ATTRIBUTE) ? Ascii.toLowerCase(value) : value;
  }

  /**

          public String apply(String value) {
            return Ascii.toLowerCase(value);
          }
        };

    static final EntryTransformer<String, String, String> ENTRY_TRANSFORMER =
        new EntryTransformer<String, String, String>() {
          @Override
          public String transformEntry(String key, String value) {
            return Ascii.toLowerCase(value);
          }
        };
  }

 */
package okhttp3

import kotlinx.serialization.Serializable
import kotlinx.serialization.decodeFromString
import kotlinx.serialization.json.Json

/**
 * A test from the [Web Platform To ASCII](https://github.com/web-platform-tests/wpt/blob/master/url/resources/toascii.json).
 *
 * Each test is a line of the file `toascii.json`.
 */
@Serializable
class WebPlatformToAsciiData {
  var input: String? = null

    }

    @Override
    protected int writeParametersWireFormat(final byte[] dst, int dstIndex) {
        final int start = dstIndex;
        byte[] descr;

        try {
            descr = DESCR.getBytes("ASCII");
        } catch (final UnsupportedEncodingException uee) {
            return 0;
        }

        SMBUtil.writeInt2(NET_SHARE_ENUM, dst, dstIndex);
        dstIndex += 2;

    /**
     * Target must be a directory flag.
     */
    int FLAGS_TARGET_MUST_BE_DIRECTORY = 0x0002;
    /**
     * Copy target in ASCII mode flag.
     */
    int FLAGS_COPY_TARGET_MODE_ASCII = 0x0004;
    /**
     * Copy source in ASCII mode flag.
     */
    int FLAGS_COPY_SOURCE_MODE_ASCII = 0x0008;
    /**
     * Verify all write operations flag.
     */

      return "CharMatcher.breakingWhitespace()";
    }
  }

  /** Implementation of {@link #ascii()}. */
  private static final class Ascii extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new Ascii();

    Ascii() {
      super("CharMatcher.ascii()");
    }

    @Override
    public boolean matches(char c) {
      return c <= '\u007f';
    }
  }

        dstIndex += 2;

        /*
         * windows98 has what appears to be another 4 0's followed by the share
         * name as a zero terminated ascii string "\TMP" + '\0'
         *
         * As is this works, but it deviates from the spec section 4.1.6.6 but
         * maybe I should put it in. Wonder what NT does?
         */

        return dstIndex - start;

  + No trailing period
  + Keep the title as short as possible. ideally under 76 characters or shorter
+ No Markdown
+ The first PR comment (this one) is wrapped at 76 characters, unless it's
  really needed (ASCII art, table, or long link)
+ If there is a corresponding issue, add either `Fixes #1234` or `Updates #1234`
  (the latter if this is not a complete fix) to this comment
+ If referring to a repo other than `golang/go` you can use the

    if (concurrencyLevel != UNSET_INT) {
      s.add("concurrencyLevel", concurrencyLevel);
    }
    if (keyStrength != null) {
      s.add("keyStrength", Ascii.toLowerCase(keyStrength.toString()));
    }
    if (valueStrength != null) {
      s.add("valueStrength", Ascii.toLowerCase(valueStrength.toString()));
    }
    if (keyEquivalence != null) {
      s.addValue("keyEquivalence");
    }
    return s.toString();
  }