Add possibility to stream requests to AWS endpoints

[thekid]

Example

Given the following S3 upload:

$s3= $this->environment->endpoint('s3')->using('bucket');

$file= 'PNG<large amount of binary data>';
$path= 'target/upload.png';
$headers= [
  'x-amz-content-sha256' => hash('sha256', $file),
  'Content-Type'         => 'image/png',
  'Content-Length'       => strlen($file),
];

The following blocks until the entire file buffer has been transmitted:

$r= $s3->request('PUT', $path, $headers, $file);

The new method allows to transmit in smaller chunks (e.g. 16 kB) and yield control between:

const CHUNK= 16384;

$transfer= $s3->open('PUT', $path, $headers);
for ($i= 0; $i < strlen($file); $i+= CHUNK) {
  $transfer->write(substr($file, $i, CHUNK));
  // e.g. yield
}
$r= $transfer->finish();

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Note there are also multipart uploads which solve the problem of have to know the size and hash beforehand!

[thekid]

Released in https://github.com/xp-forge/aws/releases/tag/v1.7.0