static byte[] concatZeros(final byte[] a, final int n) {
    byte[] c = new byte[a.length + n];
    Arrays.fill(c, (byte) 0);
    System.arraycopy(a, 0, c, 0, a.length);
    return c;
  }
Create a corpus

@param dirs The directory to store the corpus files
testfuzz/src/main/java/org/hyperledger/besu/testfuzz/javafuzz/Corpus.java