hpack/src/main/java/com/twitter/hpack/Encoder.java
private static int hash(byte[] name) {
    int h = 0;
    for (int i = 0; i < name.length; i++) {
      h = 31 * h + name[i];
    }
    if (h > 0) {
      return h;
    } else if (h == Integer.MIN_VALUE) {
      return Integer.MAX_VALUE;
    } else {
      return -h;
    }
  }
private static int hash(byte[] name) {
    int h = 0;
    for (int i = 0; i < name.length; i++) {
      h = 31 * h + name[i];
    }
    if (h > 0) {
      return h;
    } else if (h == Integer.MIN_VALUE) {
      return Integer.MAX_VALUE;
    } else {
      return -h;
    }
  }
Returns the hash code for the given header field name.