feat: add pendingStake to transcoder and pool objects

Adds a `pendingStake` field to both the `Transcoder` and `Pool` entities to
track pending bonded stake.

Author: rickstaa

schema.graphql

@@ -86,6 +86,8 @@ type Transcoder @entity {
   feeShareUpdateTimestamp: Int!
   "Total tokens delegated toward a transcoder (including their own)"
   totalStake: BigDecimal!
+  "Pending bonded stake for the transcoder since last claiming rewards"
+  pendingStake: BigDecimal!
   "Total fees generated by the transcoder in ETH (before distribution to delegators)"
   totalVolumeETH: BigDecimal!
   "Total fees generated by the transcoder in ETH (before distribution and in past 30 days)"
@@ -129,6 +131,8 @@ type Pool @entity {
   rewardTokens: BigDecimal
   "Transcoder's total stake during the earnings pool's round"
   totalStake: BigDecimal!
+  "Pending bonded stake for the transcoder since last claiming rewards"
+  pendingStake: BigDecimal!
   "Transcoder's reward cut during the earnings pool's round"
   rewardCut: BigInt!
   "Transcoder's fee share during the earnings pool's round"

src/mappings/bondingManager.ts

@@ -1,4 +1,4 @@
-import { store } from "@graphprotocol/graph-ts";
+import { Address, store } from "@graphprotocol/graph-ts";
 import {
   convertToDecimal,
   createOrLoadDelegator,
@@ -8,6 +8,7 @@ import {
   createOrLoadTranscoder,
   EMPTY_ADDRESS,
   getBlockNum,
+  integerFromString,
   makeEventId,
   makePoolId,
   makeUnbondingLockId,
@@ -500,6 +501,16 @@ export function reward(event: Reward): void {
   pool!.feeShare = transcoder.feeShare;
   pool!.rewardCut = transcoder.rewardCut;
 
+  let bondingManager = BondingManager.bind(event.address);
+  let pendingStake = convertToDecimal(
+    bondingManager.pendingStake(
+      Address.fromString(transcoder.id),
+      integerFromString(round.id)
+    )
+  );
+  transcoder.pendingStake = pendingStake;
+  pool.pendingStake = pendingStake;
+
   transcoder.save();
   delegate.save();
   pool!.save();