In Fuel, a type called Bytes represents a collection of tightly-packed bytes. The Rust SDK represents Bytes as Bytes(Vec<u8>). Here's an example of using Bytes in a contract call:
let bytes =Bytes(vec![40, 41, 42]);contract_methods.accept_bytes(bytes).call().await?;
If you have a hexadecimal value as a string and wish to convert it to Bytes, you may do so with from_hex_str:
let hex_str ="0101010101010101010101010101010101010101010101010101010101010101";let bytes =Bytes::from_hex_str(hex_str)?;assert_eq!(bytes.0, vec![1u8; 32]);// With the `0x0` prefixlet hex_str ="0x0101010101010101010101010101010101010101010101010101010101010101";let bytes =Bytes::from_hex_str(hex_str)?;assert_eq!(bytes.0, vec![1u8; 32]);