Proposed a fix handling negative values on read and write

[lombare]

Hello,

I'm currently encountering a compatibility issue between this library and Go's standard library bufio.Reader.
When the Read method returns a negative n, bufio.Reader panics.

It is common in C (and expected) for read/write functions to return a negative value to signal an error. However, in Go we have a separate error return value for this purpose, and the io.Reader contract requires n to be non-negative (specifically 0 <= n <= len(p)).
To prevent the panic and align with Go conventions, I added a fix that ensures n is never negative by clamping it to a minimum of 0 for both Read and Write methods.

Here are some references on this matter :

• Effective Go — Multiple return values: https://go.dev/doc/effective_go#multiple-returns
• io.Reader interface: https://go.dev/src/io/io.go

Thank you in advance for your time and library !