public static void writeSignedVL(long data, DataOutput out) throws IOException {
    writeUnsignedVL(encodeZigZag64(data), out);
  }
Encode a signed long as a variable length array.

This method is appropriate for signed integers. It uses zig zag encoding to so that negative
numbers will be represented more compactly. For unsigned values, writeUnsignedVL will be more
efficient.
geode-core/src/main/java/org/apache/geode/internal/InternalDataSerializer.java