ZF-6729: Add support for streaming file uploads to Amazon S3
Currently the full file data need to be passed to putObject(), and can cause problems with PHP's memory limit with large files.
Specifying a file name or PHP steam from which the data is gradually copied (without putting it into a PHP string) when the HTTP request is actually made would be better. This most likely requires changes in Zend_HTTP_Client and its adapters as well. As for the Socket adapter, using stream_copy_to_stream() works perfect.
Slightly related to some elements of the comments on ZF-3758