Revert "Cache eth_calls with in-memory cache (#410)" (#412)

This reverts commit 1209099.

lib/handlers/evm/provider/InstrumentedEVMProvider.ts

@@ -25,50 +25,11 @@ export type InstrumentedEVMProviderProps = {
 export class InstrumentedEVMProvider extends ethers.providers.StaticJsonRpcProvider {
   private readonly name: ProviderName
   private readonly metricPrefix: string
-  private readonly blockCache: Map<string, Promise<any>>
 
   constructor({ url, network, name }: InstrumentedEVMProviderProps) {
     super(url, network)
     this.name = name
     this.metricPrefix = `RPC_${this.name}_${this.network.chainId}`
-    this.blockCache = new Map()
-    // Set an event listener to clear the cache on every new block.
-    this.on('block', () => {
-      metric.putMetric('RPCProviderCacheClear', 1, MetricLoggerUnit.Count)
-      this.blockCache.clear()
-    })
-  }
-
-  // Adds caching functionality to the RPC provider
-  override send(method: string, params: Array<any>): Promise<any> {
-    // Only cache eth_call's.
-    if (method !== 'eth_call') return super.send(method, params)
-    let key: string | undefined = undefined
-
-    try {
-      key = `call:${JSON.stringify(params)}`
-    } catch (e) {
-      metric.putMetric('RPCProviderCacheKeyError', 1, MetricLoggerUnit.Count)
-    }
-
-    if (key) {
-      const cached = this.blockCache.get(key)
-      if (cached) {
-        metric.putMetric('RPCProviderCacheHit', 1, MetricLoggerUnit.Count)
-        return cached
-      } else {
-        metric.putMetric('RPCProviderCacheMiss', 1, MetricLoggerUnit.Count)
-      }
-    }
-
-    const result = super.send(method, params)
-
-    if (key) {
-      metric.putMetric('RPCProviderCacheInsert', 1, MetricLoggerUnit.Count)
-      this.blockCache.set(key, result)
-    }
-
-    return result
   }
 
   override call(transaction: Deferrable<TransactionRequest>, blockTag?: BlockTag | Promise<BlockTag>): Promise<string> {