Add offset prefixes to EpochRewards

proposals/0118-partitioned-epoch-reward-distribution.md

@@ -147,28 +147,29 @@ include: the parameters needed to recalculate the reward partitions, the total
 rewards to be distributed, and the amount of rewards distributed so far.
 
 The layout of `EpochRewards` sysvar is shown in the following pseudo code.
+Prefixes indidate the offset of each field, and padding bytes are always zero.
 
 ```
-#[repr(C)] // C representation, ie. 8-byte alignment
+#[repr(C)] // C representation, 8-byte alignment
 struct EpochRewards{
    // whether the rewards period (calculation and distribution) is active
-   active: bool, // byte. false: 0x00, true: 0x01
+   /* 0x00 */ active: bool, // byte. false: 0x00, true: 0x01
 
-   distribution_starting_block_height: u64, // little-endian unsigned 64-bit integer
+   /* 0x08 */ distribution_starting_block_height: u64, // little-endian unsigned 64-bit integer
    
-   num_partitions: u64, // little-endian unsigned 64-bit integer
+   /* 0x10 */ num_partitions: u64, // little-endian unsigned 64-bit integer
    
-   parent_blockhash: Hash, // byte-array of length 32
+   /* 0x18 */ parent_blockhash: Hash, // byte-array of length 32
 
    // total points calculated for the current epoch, where points equals the sum
    // of delegated stake * credits observed for all delegations
-   total_points: u128, // little-endian unsigned 128-bit integer
+   /* 0x38 */ total_points: u128, // little-endian unsigned 128-bit integer
 
    // total rewards for the current epoch, in lamports
-   total_rewards: u64, // little-endian unsigned 64-bit integer
+   /* 0x48 */ total_rewards: u64, // little-endian unsigned 64-bit integer
 
    // distributed rewards for the current epoch, in lamports
-   distributed_rewards: u64, // little-endian unsigned 64-bit integer
+   /* 0x50 */ distributed_rewards: u64, // little-endian unsigned 64-bit integer
 }
 ```