Wrap storage calls with encoding checks

[briankassouf]

No description provided.

[tyrannosaurus-becks]

There's a test failure that looks related:

--- FAIL: TestHandler_nonPrintableChars (0.04s)
    handler_test.go:665: Expected status 204, got 500. Body:
        
        {"errors":["1 error occurred:\n\t* failed to write: key contains non-printable characters\n\n"]}