final int beginIndex = pos;
while (pos < buffer.length() && !HTTP.isWhitespace(buffer.charAt(pos))) {
pos++;
}
final int endIndex = pos;
final String s = buffer.substring(beginIndex, endIndex);
if (!s.equalsIgnoreCase(getSchemeName())) {
throw new MalformedChallengeException("Invalid scheme identifier: " + s);
}
parseChallenge(buffer, pos, buffer.length());