Normalizing top-level documents as arrays will allow single and multi-document checks to be more flexible. This will not extend to embedded documents, where we'll still need to be explicit.

Additionally, assertSameDocuments can now operate on any array or Traversable without needing to set its own type map.

Unless the operation returns a scalar or custom value (e.g. Count, CreateIndexes), we should explicitly convert documents to stdClass instances to return. This will ultimately be made configurable once PHPLIB-112 is implemented.

A manual cast (of arrays to objects) was also necessary until PHPC-318 is implemented.

Because the typemap says 'document as array', we now need to change the return value with a cast to 'object'

Perhaps, an alternative could be to use access properties instead of array
elements?

Additionally, this changes createIndexes() to no longer allow an empty array as input. The index management spec doesn't state that empty input must be accepted, so I'm not sure why we had that behavior.

Invalid arguments and options constitute a logic error, so InvalidArgumentTypeException may be used. For runtime errors (e.g. server returned something we didn't expect), UnexpectedValueTypeException may be used.

Syntax error typo

Let's also not assume that origin is the appropriate upstream remote (it may be a local fork).