By either defining their types or renaming to match parent class (or
interface).

The blob type maps BLOB (and also TEXT) columns to PHP streams.
Internally, they use the ParameterType::LARGE_OBJECT (i. e. \PDO::PARAM_LOB)
binding type, which suggests that efficient handling of PHP stream resources
was intended.

However, at least when using the mysqli driver, stream resources passed into
insert() or update() are simply cast to strings. As a result, a literal
string like "Resource id #126" will end up in the database.

This PR fixes the issue by correctly processing streams in the
MysqliStatement when they are passed with the ParameterType::LARGE_OBJECT
binding type. It uses the mysqli::send_long_data() method to pass stream
data in chunks to the MySQL server, thus keeping the memory footprint low.

This method does not (despite claims to the contrary) allow to bypass the
max_allowed_package size!

The pdo_mysql driver was already capable of handling streams this way.
Now this is covered by tests.

Helpful documentation:

- http://php.net/manual/en/mysqli-stmt.send-long-data.php
- http://php.net/manual/en/mysqli-stmt.bind-param.php - see first "Note"
- http://php.net/manual/en/pdo.lobs.php
- https://blogs.oracle.com/oswald/phps-mysqli-extension:-storing-and-retrieving-blobs

Additional notes on MySQL's max_allowed_packet:

This change does not not intend to work around the max_allowed_packet setting,
and quick tests show that this is not possible: When MySQL is configured to use
a low max_allowed_packet value, an error will be triggered stating

  Parameter of prepared statement which is set through
  mysql_send_long_data() is longer than 'max_allowed_packet' bytes.

Documentation for the underlying mysql_stmt_send_long_data() C API function
suggests that max_allowed_packet is always a hard limit.

References:

- https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-send-long-data.html
- https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_max_allowed_packet
- https://bugs.mysql.com/bug.php?id=83958

What mysqli::send_long_data() seems to do is that every data chunk of data
passed to it is immediately sent out to the network. I have confirmed this
using tcpdump, and so the advantage might be that we can keep the memory
footprint low on the PHP side while processing streams.

As discussed in #3217 (see https://github.com/doctrine/dbal/pull/3217#issuecomment-419673323 in particular), there is no way in MySQL to get around the `max_allowed_packet` limitation.

Fixes #2953.

statements in a rewindable iterator. Skipped the test for iterating
multiple times with a message regarding that iterators are non
rewindable.

Only added to mysqli for now, can add to other drivers (assuming they
support reseting the pointer in some way) after feedback.

I don't really understand the mysqli driver too much and the changes
break the tests so undo using an iterator for this particular driver.

Allows result sets to be iterated over without running out of memory on
large data sets.

The current driver has no option to allow the usage of SSL connections on mysql. I've used the same name params as mysql client.
An example of mysql client usage would be:

mysql --ssl-ca='path_to_ca.pem' --ssl-cert='path_to_client_cert.pem' --ssl-key='path_to_client_key.pem'

refactor secure connection as params

remove space

add space

refactor secure connection

rename method

rename method

docs: add ssl params to use in mysqli driver

rename test method

refactor method setSecureConnection

fix bug

add comment to method

remove string escaping