Faster BeaconState enc/dec (#671)

* Add state enc/dec benches

* Add example for flamegraph

* Use `PublicKeyBytes` for `Validator`

* Ripple PublicKeyBytes change through codebase

* Add benches, optimizations to store BeaconState

* Store BeaconState in StorageContainer too

* Optimize StorageContainer with std::mem magic

* Fix rest_api tests

eth2/types/src/beacon_state.rs

@@ -268,7 +268,7 @@ impl<T: EthSpec> BeaconState<T> {
     /// returns `None`.
     ///
     /// Requires a fully up-to-date `pubkey_cache`, returns an error if this is not the case.
-    pub fn get_validator_index(&self, pubkey: &PublicKey) -> Result<Option<usize>, Error> {
+    pub fn get_validator_index(&self, pubkey: &PublicKeyBytes) -> Result<Option<usize>, Error> {
         if self.pubkey_cache.len() == self.validators.len() {
             Ok(self.pubkey_cache.get(pubkey))
         } else {
@@ -860,7 +860,7 @@ impl<T: EthSpec> BeaconState<T> {
             .enumerate()
             .skip(self.pubkey_cache.len())
         {
-            let success = self.pubkey_cache.insert(validator.pubkey.clone(), i);
+            let success = self.pubkey_cache.insert(validator.pubkey.clone().into(), i);
             if !success {
                 return Err(Error::PubkeyCacheInconsistent);
             }

eth2/types/src/beacon_state/pubkey_cache.rs

@@ -10,7 +10,7 @@ pub struct PubkeyCache {
     /// len, as it does not increase when duplicate keys are added. Duplicate keys are used during
     /// testing.
     len: usize,
-    map: HashMap<PublicKey, ValidatorIndex>,
+    map: HashMap<PublicKeyBytes, ValidatorIndex>,
 }
 
 impl PubkeyCache {
@@ -23,7 +23,7 @@ impl PubkeyCache {
     ///
     /// The added index must equal the number of validators already added to the map. This ensures
     /// that an index is never skipped.
-    pub fn insert(&mut self, pubkey: PublicKey, index: ValidatorIndex) -> bool {
+    pub fn insert(&mut self, pubkey: PublicKeyBytes, index: ValidatorIndex) -> bool {
         if index == self.len {
             self.map.insert(pubkey, index);
             self.len += 1;
@@ -34,7 +34,7 @@ impl PubkeyCache {
     }
 
     /// Looks up a validator index's by their public key.
-    pub fn get(&self, pubkey: &PublicKey) -> Option<ValidatorIndex> {
+    pub fn get(&self, pubkey: &PublicKeyBytes) -> Option<ValidatorIndex> {
         self.map.get(pubkey).copied()
     }
 }

eth2/types/src/test_utils/builders/testing_beacon_state_builder.rs

@@ -109,7 +109,7 @@ impl<T: EthSpec> TestingBeaconStateBuilder<T> {
                 ));
 
                 Validator {
-                    pubkey: keypair.pk.clone(),
+                    pubkey: keypair.pk.clone().into(),
                     withdrawal_credentials,
                     // All validators start active.
                     activation_eligibility_epoch: T::genesis_epoch(),

eth2/types/src/validator.rs

@@ -1,4 +1,4 @@
-use crate::{test_utils::TestRandom, Epoch, Hash256, PublicKey};
+use crate::{test_utils::TestRandom, Epoch, Hash256, PublicKeyBytes};
 
 use serde_derive::{Deserialize, Serialize};
 use ssz_derive::{Decode, Encode};
@@ -10,7 +10,7 @@ use tree_hash_derive::TreeHash;
 /// Spec v0.9.1
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Encode, Decode, TestRandom, TreeHash)]
 pub struct Validator {
-    pub pubkey: PublicKey,
+    pub pubkey: PublicKeyBytes,
     pub withdrawal_credentials: Hash256,
     pub effective_balance: u64,
     pub slashed: bool,
@@ -46,7 +46,7 @@ impl Default for Validator {
     /// Yields a "default" `Validator`. Primarily used for testing.
     fn default() -> Self {
         Self {
-            pubkey: PublicKey::default(),
+            pubkey: PublicKeyBytes::empty(),
             withdrawal_credentials: Hash256::default(),
             activation_eligibility_epoch: Epoch::from(std::u64::MAX),
             activation_epoch: Epoch::from(std::u64::MAX),