Handle concurrent clients implicitly within the SFTP server EventListener

### Description

I need to handle multiple users and multiple commands from each user.
For example multiple clients are executing put command to the SFTP server, in this case, I want to read the data in the `SFTPEventListener` class and do some processing.
But I saw that the class instance is shared amongst multiple users and multiple user sessions, due to which I am not able maintain any state inside the `SFTPEventListener`. Although I can write my own implementation to handle this scenario but it would have been better if there was an implicit handle given in the library.

### Motivation

By adding this, concurrent user requests can be implicitly handled in the library.

### Alternatives considered

_No response_

### Additional context

_No response_

Start by reading the SFTPEventListener class and tracing how its instance is shared across users and sessions. The issue does not name a file, test, or concrete API and does not define how implicit concurrent handling should behave, so those requirements need clarification before implementation.

Written by the indexing model from the issue text.