Added crc32 integrity check in message.rs. Fixed little variable name typo

[LorenzoTettamanti]

Hi everyone, this PR adds a CRC32 integrity check in the decode functions in message.rs (it was previously annotated as TODO).

Tests

• cargo test: all checks passed:
  • 24/24 passed
  • 0 ignored
  • 0 failed
• Verified end-to-end with the producer and consumer example.

[LorenzoTettamanti]

Fixed the cargo clippy error during lint check @BewareMyPower

[BewareMyPower]

Please fix the lint errors, you can run cargo fmt --all --check locally to check the code format.

[LorenzoTettamanti]

@BewareMyPower done