Demotest Rust Hasher who return the Square Sum of the hashed values

lib.rs

use std::hash::Hasher;
use std::hash::BuildHasher;

struct SquareSumHasher {
    state: u64,
}

impl SquareSumHasher {
    fn new(state: u64) -> Self {
        SquareSumHasher { state }
    }
}

impl Hasher for SquareSumHasher {
    fn finish(&self) -> u64 {
        self.state
    }
    fn write(&mut self, bytes: &[u8]) {
        for i in bytes {
            self.write_u8(*i);
        }
    }

    fn write_u8(&mut self, i: u8) { self.state += (i as u64).pow(2); }
    fn write_u16(&mut self, i: u16) { self.state += (i as u64).pow(2); }
    fn write_u32(&mut self, i: u32) { self.state += (i as u64).pow(2); }
    fn write_u64(&mut self, i: u64) { self.state += (i as u64).pow(2); }
    fn write_usize(&mut self, i: usize) { self.state += (i as u64).pow(2); }
    fn write_i8(&mut self, i: i8) { self.state += (i.abs() as u64).pow(2); }
    fn write_i16(&mut self, i: i16) { self.state += (i.abs() as u64).pow(2); }
    fn write_i64(&mut self, i: i64) { self.state += (i.abs() as u64).pow(2); }
    fn write_i32(&mut self, i: i32) { self.state += (i.abs() as u64).pow(2); }
    fn write_isize(&mut self, i: isize) { self.state += (i.abs() as u64).pow(2); }
}

struct BuildSquareSumHasher {}

impl BuildSquareSumHasher {
    fn new() -> BuildSquareSumHasher {
        BuildSquareSumHasher {}
    }
}

impl BuildHasher for BuildSquareSumHasher {
    type Hasher = SquareSumHasher;
    fn build_hasher(&self) -> Self::Hasher {
        Self::Hasher::new(0_u64)
    }
}