Warning: Not cryptographically secure.
Examples:
```rust use nearsdk::borsh::{self, BorshDeserialize, BorshSerialize}; use nearsdk::{env, nearbindgen}; use nearrng::{Rng};
nearsdk::setupalloc!();
pub struct Counter { val: i32, }
impl Counter { pub fn increment(&mut self) { let mut rng = Rng::new(&env::randomseed()); let value = rng.randrange_i32(0, 20); self.val += value; } } ```