code: public void appendFloat(float x) {
          ByteArrayOutputStream buffer = new ByteArrayOutputStream(4);
          DataOutputStream bufout = new DataOutputStream(buffer);
          try {
              bufout.writeFloat(x);
              appendBytes(buffer.toByteArray(), 0, 4);
          } catch (IOException e) {
              throw new AssertionError("write");
          }
      }
docs: Append a float as a four byte number.