pocketmine\nbt\NBT::putDouble PHP Method

    public function putDouble($v)
    {
        $this->buffer .= $this->endianness === self::BIG_ENDIAN ? Binary::writeDouble($v) : Binary::writeLDouble($v);
    }

 public function write(NBT $nbt)
 {
     $nbt->putDouble($this->value);
 }