Potentially improper use of BinaryReader

[GrabYourPitchforks]

1. BinaryReader defaults to Encoding.UTF8, which replaces invalid UTF-8 data with the U+FFFD replacement char. This differs from both the MS-NRBF spec and the existing BinaryFormatter behavior, which requires well-formed UTF-8. Consider creating a UTF8Encoding instance using the public ctor and passing throwOnInvalidBytes: true, then using that for all operations.

2. BinaryReader.ReadString does not enforce minimal-representation 7-bit encoded integers, though MS-NRBF requires it. Either: (a) reimplement the ReadString helper method yourself to enforce minimal representation; or (b) explicitly document that the reader does not enforce this aspect of the spec, and document the consequences resulting from it.