I am able to see my custom error messages (defined on chain) when I call the [anchor] program using javascript client `node client.js`: 

    error: {
        errorCode: { code: 'MEOW', number: 6003 },
        errorMessage: 'This account a custom err message that I have written',
        comparedValues: undefined,
        origin: { file: 'programs/helloworld/src/lib.rs', line: 46 }
      },

the errorCode and errorMessage are especially helpful. How can I print those fields using Rust? Right now, I am only getting

    Error: RPC response error -32002: Transaction simulation failed: Error processing Instruction 0: custom program error: 0x1774 [5 log messages]
    
    Caused by:
        0: RPC response error -32002: Transaction simulation failed: Error processing Instruction 0: custom program error: 0x1774 [5 log messages]
        1: RPC response error -32002: Transaction simulation failed: Error processing Instruction 0: custom program error: 0x1774 [5 log messages]

my rust client code follows this template:

    fn main() -> Result<()> {
        call_instruction()?,
        Ok(())
    }
    
    fn call_instruction() -> Result <()> {
        let program = ...;
    
        let signature = program
        .request()
        .accounts(program::accounts::Test {
            user: program.payer(),
        }).args(program::instruction::Testing {}).send()?;
    
        println!("Transaction signature: {:?}",signature);
        Ok(())
    }

In terminal, I have tried setting env variable `RUSTLOG=solana_client=debug` before running `cargo run`, but nothing happens :(