fn initialize(env: soroban_sdk::Env, admin: soroban_sdk::Address, initial_supply: i128)
fn transfer(
env: soroban_sdk::Env,
from: soroban_sdk::Address,
to: soroban_sdk::Address,
amount: i128,
)
fn balance_of(env: soroban_sdk::Env, owner: soroban_sdk::Address) -> i128