v0.4.0

A major feature release with a significant documentation overhaul and long overdue API cleanup!

This update involves a number of BC breaks due to various changes to make the
API more consistent with the ReactPHP ecosystem. In particular, this now uses
promises consistently as return values instead of accepting callback functions
and this now offers an additional streaming API for processing very large result
sets efficiently.

We realize that the changes listed below may seem a bit overwhelming, but we've
tried to be very clear about any possible BC breaks. See below for changes you
have to take care of when updating from an older version.

• Feature / BC break: Add Factory to simplify connecting and keeping connection state,
  mark Connection class as internal and remove connect() method.
  (#64 by @clue)

  // old
  $connection = new Connection($loop, $options);
  $connection->connect(function (?Exception $error, $connection) {
      if ($error) {
          // an error occured while trying to connect or authorize client
      } else {
          // client connection established (and authenticated)
      }
  });
  
  // new
  $factory = new Factory($loop);
  $factory->createConnection($url)->then(
      function (ConnectionInterface $connection) {
          // client connection established (and authenticated)
      },
      function (Exception $e) {
          // an error occured while trying to connect or authorize client
      }
  );

• Feature / BC break: Use promises for query() method and resolve with QueryResult on success and
  and mark all commands as internal and move its base to Commands namespace.
  (#61 and #62 by @clue)

  // old
  $connection->query('CREATE TABLE test');
  $connection->query('DELETE FROM user WHERE id < ?', $id);
  $connection->query('SELECT * FROM user', function (QueryCommand $command) {
      if ($command->hasError()) {
          echo 'Error: ' . $command->getError()->getMessage() . PHP_EOL;
      } elseif (isset($command->resultRows)) {
          var_dump($command->resultRows);
      }
  });
  
  // new
  $connection->query('CREATE TABLE test');
  $connection->query('DELETE FROM user WHERE id < ?', [$id]);
  $connection->query('SELECT * FROM user')->then(function (QueryResult $result) {
      var_dump($result->resultRows);
  }, function (Exception $error) {
      echo 'Error: ' . $error->getMessage() . PHP_EOL;
  });

• Feature / BC break: Add new queryStream() method to stream result set rows and
  remove undocumented "results" event.
  (#57 and #77 by @clue)

  $stream = $connection->queryStream('SELECT * FROM users');
  
  $stream->on('data', function ($row) {
      var_dump($row);
  });
  $stream->on('end', function () {
      echo 'DONE' . PHP_EOL;
  });

• Feature / BC break: Rename close() to quit(), use promises for quit() method and
  add new close() method to force-close the connection.
  (#65 and #76 by @clue)

  // old: soft-close/quit
  $connection->close(function () {
      echo 'closed';
  });
  
  // new: soft-close/quit
  $connection->quit()->then(function () {
      echo 'closed';
  });
  
  // new: force-close
  $connection->close();

• Feature / BC break: Use promises for ping() method and resolve with void value on success.
  (#63 and #66 by @clue)

  // old
  $connection->ping(function ($error, $connection) {
      if ($error) {
          echo 'Error: ' . $error->getMessage() . PHP_EOL;
      } else {
          echo 'OK' . PHP_EOL;
      }
  });
  
  // new 
  $connection->ping(function () {
      echo 'OK' . PHP_EOL;
  }, function (Exception $error) {
      echo 'Error: ' . $error->getMessage() . PHP_EOL;
  });

• Feature / BC break: Define events on ConnectionInterface
  (#78 by @clue)

• BC break: Remove unneeded ConnectionInterface methods getState(),
  getOptions(), setOptions() and getServerOptions(), selectDb() and listFields() dummy.
  (#60 and #68 by @clue)

• BC break: Mark all protocol logic classes as internal and move to new Io namespace.
  (#53 and #62 by @clue)

• Fix: Fix executing queued commands in the order they are enqueued
  (#75 by @clue)

• Fix: Fix reading all incoming response packets until end
  (#59 by @clue)

• [maintenance] Internal refactoring to simplify connection and authentication logic
  (#69 by @clue)

• [maintenance] Internal refactoring to remove unneeded references from Commands
  (#67 by @clue)

• [maintenance] Internal refactoring to remove unneeded EventEmitter implementation and circular references
  (#56 by @clue)

• [maintenance] Refactor internal parsing logic to separate Buffer class, remove dead code and improve performance
  (#54 by @clue)