code: public BitArray getUnalignedBitString(boolean tagImplicit)
      throws IOException {
          if (!tagImplicit) {
              if (tag != tag_BitString)
                  throw new IOException("DerValue.getBitString, not a bit string "
                                         + tag);
              }
          return buffer.getUnalignedBitString();
      }
docs: Returns an ASN.1 BIT STRING value, with the tag assumed implicit
  based on the parameter.  The bit string need not be byte-aligned.
  
  @params tagImplicit if true, the tag is assumed implicit.
  @return the bit string held in this value