Function transfer 

pub async fn transfer(
    agent: &SolanaAgentKit,
    to: &str,
    amount: u64,
    mint: Option<String>,
) -> Result<String, ClientError>

Transfer SOL or SPL tokens to a recipient

agent - SolanaAgentKit instance to - Recipient’s public key amount - Amount to transfer mint - Optional mint address for SPL tokens

Returns the transaction signature.