code: public void writeDateTime(Date date) throws IOException {
  		_writeArrayFieldNameIfNeeded();
  		_verifyValueWrite("write datetime");
  		_buffer.putByte(_typeMarker, BsonConstants.TYPE_DATETIME);
  		_buffer.putLong(date.getTime());
  		flushBuffer();
  	}
docs: Write a BSON date time
  
  @param date The date to write
  @throws IOException If an error occurred in the stream while writing