pocketmine\level\Level::setBlock PHP Method

    public function setBlock(Vector3 $pos, Block $block, bool $direct = false, bool $update = true) : bool
    {
        $pos = $pos->floor();
        if ($pos->y < 0 or $pos->y >= 128) {
            return false;
        }
        if ($this->getChunk($pos->x >> 4, $pos->z >> 4, true)->setBlock($pos->x & 0xf, $pos->y & 0x7f, $pos->z & 0xf, $block->getId(), $block->getDamage())) {
            if (!$pos instanceof Position) {
                $pos = $this->temporalPosition->setComponents($pos->x, $pos->y, $pos->z);
            }
            $block->position($pos);
            unset($this->blockCache[Level::blockHash($pos->x, $pos->y, $pos->z)]);
            $index = Level::chunkHash($pos->x >> 4, $pos->z >> 4);
            if ($direct === true) {
                $this->sendBlocks($this->getChunkPlayers($pos->x >> 4, $pos->z >> 4), [$block], UpdateBlockPacket::FLAG_ALL_PRIORITY);
                unset($this->chunkCache[$index]);
            } else {
                if (!isset($this->changedBlocks[$index])) {
                    $this->changedBlocks[$index] = [];
                }
                $this->changedBlocks[$index][Level::blockHash($block->x, $block->y, $block->z)] = clone $block;
            }
            foreach ($this->getChunkLoaders($pos->x >> 4, $pos->z >> 4) as $loader) {
                $loader->onBlockChanged($block);
            }
            if ($update === true) {
                $this->updateAllLight($block);
                $this->server->getPluginManager()->callEvent($ev = new BlockUpdateEvent($block));
                if (!$ev->isCancelled()) {
                    foreach ($this->getNearbyEntities(new AxisAlignedBB($block->x - 1, $block->y - 1, $block->z - 1, $block->x + 1, $block->y + 1, $block->z + 1)) as $entity) {
                        $entity->scheduleUpdate();
                    }
                    $ev->getBlock()->onUpdate(self::BLOCK_UPDATE_NORMAL);
                }
                $this->updateAround($pos);
            }
            return true;
        }
        return false;
    }

 public function onActivate(Level $level, Player $player, Block $block, Block $target, $face, $fx, $fy, $fz)
 {
     if ($this->meta === Item::AIR) {
         if ($target instanceof Liquid) {
             $level->setBlock($target, new Air(), true);
             if (($player->gamemode & 0x1) === 0) {
                 $this->meta = $target instanceof Water ? Item::WATER : Item::LAVA;
             }
             return true;
         }
     } elseif ($this->meta === Item::WATER) {
         //Support Make Non-Support Water to Support Water
         if ($block->getID() === self::AIR || $block instanceof Water && ($block->getDamage() & 0x7) != 0x0) {
             $water = new Water();
             $level->setBlock($block, $water, true);
             $water->place(clone $this, $block, $target, $face, $fx, $fy, $fz, $player);
             if (($player->gamemode & 0x1) === 0) {
                 $this->meta = 0;
             }
             return true;
         }
     } elseif ($this->meta === Item::LAVA) {
         if ($block->getID() === self::AIR) {
             $level->setBlock($block, new Lava(), true);
             if (($player->gamemode & 0x1) === 0) {
                 $this->meta = 0;
             }
             return true;
         }
     }
     return false;
 }