Add examples on gridfs

examples/gridfs-stream.php

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+<?php
+
+/**
+ * This example demonstrates how to use GridFS streams.
+ */
+
+declare(strict_types=1);
+
+namespace MongoDB\Examples;
+
+use MongoDB\Client;
+
+use function fclose;
+use function feof;
+use function fread;
+use function fwrite;
+use function getenv;
+use function strlen;
+
+use const PHP_EOL;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$client = new Client(getenv('MONGODB_URI') ?: 'mongodb://127.0.0.1/');
+
+$bucket = $client->test->selectGridFSBucket(['disableMD5' => true]);
+
+// Open a stream for writing, similar to fopen with mode 'w'
+$stream = $bucket->openUploadStream('hello.txt');
+
+for ($i = 0; $i < 1_000_000; $i++) {
+    fwrite($stream, 'Hello line ' . $i . PHP_EOL);
+}
+
+// Last data are flushed to the server when the stream is closed
+fclose($stream);
+
+// Open a stream for reading, similar to fopen with mode 'r'
+$stream = $bucket->openDownloadStreamByName('hello.txt');
+
+$size = 0;
+while (! feof($stream)) {
+    $data = fread($stream, 2 ** 10);
+    $size += strlen($data);
+}
+
+echo 'Read a total of ' . $size . ' bytes' . PHP_EOL;

examples/gridfs-upload.php

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+<?php
+
+/**
+ * This example demonstrates how to upload and download files from a stream with GridFS.
+ */
+
+declare(strict_types=1);
+
+namespace MongoDB\Examples;
+
+use MongoDB\BSON\ObjectId;
+use MongoDB\Client;
+
+use function assert;
+use function fclose;
+use function fopen;
+use function fwrite;
+use function getenv;
+use function rewind;
+
+use const PHP_EOL;
+use const STDOUT;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$client = new Client(getenv('MONGODB_URI') ?: 'mongodb://127.0.0.1/');
+
+$gridfs = $client->selectDatabase('test')->selectGridFSBucket();
+
+// Create an in-memory stream, this can be any stream source like STDIN or php://input for web requests
+$stream = fopen('php://temp', 'w+');
+fwrite($stream, 'Hello world!');
+rewind($stream);
+
+// Upload to GridFS from the stream
+$id = $gridfs->uploadFromStream('hello.txt', $stream);
+assert($id instanceof ObjectId);
+echo 'Inserted file with ID: ' . $id . PHP_EOL;
+fclose($stream);
+
+// Download the file and print the contents directly to STDOUT, chunk by chunk
+echo 'File contents: ';
+$gridfs->downloadToStreamByName('hello.txt', STDOUT);
+echo PHP_EOL;
+
+// Delete the file
+$gridfs->delete($id);