Seems like there are two ways of retrieving Clock according Solana docs:

1. Passing SYSVAR_CLOCK_PUBKEY into an instruction

   let clock = Clock::from_account_info(&sysvar_clock_pubkey)?;
   let current_timestamp = clock.unix_timestamp;
   

2. Accessing Clock directly inside an instruction.

   let clock = Clock::get()?;
   let current_timestamp = clock.unix_timestamp;
   

Seems like we shouldn't use external libs for this.

Seems like there are two ways of retrieving Clock according Solana docs:

1. Passing SYSVAR_CLOCK_PUBKEY into an instruction

   let clock = Clock::from_account_info(&sysvar_clock_pubkey)?;
   let current_timestamp = clock.unix_timestamp;
   

2. Accessing Clock directly inside an instruction.

   let clock = Clock::get()?;
   let current_timestamp = clock.unix_timestamp;
   

Looks like we shouldn't use external libs for this.