Apply clippy suggestion

[paq]

fix #27

[Copilot]

Pull request overview

Resolves CI failures from Clippy warnings (issue #27) by applying suggested simplifications and removing redundant conversions.

Changes:

• Simplified byte-slice writing/reading error mapping (map_err(Error::IoError)) and removed redundant temporaries.
• Removed redundant numeric casts before to_be_bytes() in multiple MessagePack writer implementations.
• Updated test/bench code to use more idiomatic Vec initialization and API call patterns.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
zerompk/tests/derive.rs	Simplifies construction of recursive-node MessagePack test payload bytes.
zerompk/src/write.rs	Removes redundant casts and simplifies error mapping in writers.
zerompk/src/read.rs	Simplifies IO error mapping in IOReader::read_exact.
zerompk/src/lib.rs	Removes unnecessary temporary variable in from_msgpack.
zerompk/src/impl.rs	Simplifies ToMessagePack impls for references and &str.
zerompk/benches/deserialize_large_array.rs	Simplifies buffer handling for msgpacker benchmark.

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[nuskey8]

Merged the PR. thanks!