parquet-common/src/main/java/org/apache/parquet/bytes/LittleEndianDataOutputStream.java
public final void writeLong(long v) throws IOException {
    writeBuffer[7] = (byte)(v >>> 56);
    writeBuffer[6] = (byte)(v >>> 48);
    writeBuffer[5] = (byte)(v >>> 40);
    writeBuffer[4] = (byte)(v >>> 32);
    writeBuffer[3] = (byte)(v >>> 24);
    writeBuffer[2] = (byte)(v >>> 16);
    writeBuffer[1] = (byte)(v >>>  8);
    writeBuffer[0] = (byte)(v >>>  0);
    out.write(writeBuffer, 0, 8);
  }
public final void writeLong(long v) throws IOException {
    writeBuffer[7] = (byte)(v >>> 56);
    writeBuffer[6] = (byte)(v >>> 48);
    writeBuffer[5] = (byte)(v >>> 40);
    writeBuffer[4] = (byte)(v >>> 32);
    writeBuffer[3] = (byte)(v >>> 24);
    writeBuffer[2] = (byte)(v >>> 16);
    writeBuffer[1] = (byte)(v >>>  8);
    writeBuffer[0] = (byte)(v >>>  0);
    out.write(writeBuffer, 0, 8);
  }
Writes a <code>long</code> to the underlying output stream as eight
bytes, low byte first. In no exception is thrown, the counter
<code>written</code> is incremented by <code>8</code>.

@param      v   a <code>long</code> to be written.
@exception  IOException  if an I/O error occurs.
@see        java.io.FilterOutputStream#out