use more optimized way to store things in state

src/nullhasher.rs

@@ -0,0 +1,40 @@
+use std::hash::{BuildHasher, Hasher};
+
+/// A dummy hasher that maps simply returns the hashed u64
+///
+/// trying to hash anything but a u64 will result in a panic
+pub struct NullHasher {
+    data: u64,
+}
+
+impl Hasher for NullHasher {
+    #[inline]
+    fn finish(&self) -> u64 {
+        self.data
+    }
+
+    #[inline]
+    fn write(&mut self, _msg: &[u8]) {
+        panic!("can only hash u64 as u32");
+    }
+
+    #[inline]
+    fn write_u32(&mut self, data: u32) {
+        self.data = data as u64
+    }
+
+    #[inline]
+    fn write_u64(&mut self, data: u64) {
+        self.data = data;
+    }
+}
+
+pub struct NullHasherBuilder;
+
+impl BuildHasher for NullHasherBuilder {
+    type Hasher = NullHasher;
+
+    fn build_hasher(&self) -> Self::Hasher {
+        NullHasher { data: 0 }
+    }
+}