Removed "cache keys" section from readme.

Author: Bilge

README.md

@@ -174,12 +174,12 @@ Porter includes one transformer, `FilterTransformer`, that removes records from
 Transformers implement the `Transformer` interface that defines one method with the following signature.
 
 ```php
-public function transform(RecordCollection $records, $context) : RecordCollection;
+public function transform(RecordCollection $records, $context): RecordCollection;
 ```
 
 When `transform()` is called the transformer may iterate each record and change it in any way, including removing or inserting additional records. The record collection must be returned by the method, whether or not changes were made.
 
-Transformers should also implement the `__clone` magic method if the they store any object state in order to facilitate deep copy when Porter clones the owning `ImportSpecification` during an import.
+Transformers should also implement the `__clone` magic method if the they store any object state, in order to facilitate deep copy when Porter clones the owning `ImportSpecification` during import.
 
 Filtering
 ---------
@@ -188,7 +188,7 @@ Filtering provides a way to remove some records. For each record, if the specifi
 
 In general we would like to avoid filtering because it is inefficient to import data and then immediately remove some of it, but some immature APIs do not provide a way to reduce the data set on the server, so filtering on the client is the only alternative. Filtering also invalidates the record count reported by some resources, meaning we no longer know how many records are in the collection before iteration.
 
-#### Example
+### Example
 
 The following example filters out any records that do not have an *id* field present.
 
@@ -225,7 +225,7 @@ Any connector can be wrapped in a `CachingConnector` to provide [PSR-6][PSR-6] c
 
 Remember that whilst using a `CachingConnector` enables caching, caching must also be enabled on a per-import basis by calling `ImportSpecification::enableCache()`.
 
-#### Example
+### Example
 
 The follow example enables connector caching.
 
@@ -236,34 +236,6 @@ $records = $porter->import(
 );
 ```
 
-### Cache keys
-
-The cache key is generated by a `CacheKeyGenerator` that encodes the source and connector options to produce a unique cache key for each distinct `Connector::fetch` request. The default `JsonCacheKeyGenerator` simply JSON-encodes the parameters to create a cache key. The cache key generation strategy may be changed by calling `CachingConnector::setCacheKeyGenerator`.
-
-#### Writing a cache key generator
-
-The `CacheKeyGenerator` interface defines one method with the following interface.
-
-```php
-public function generateCacheKey(string $source, array $sortedOptions) : string;
-```
-
-Implementations receive the source of the fetch request and an array and sorted options, so that options originally specified in a different order still result in the same cache key. The method must return a [PSR-6][PSR-6] compatible cache key.
-
-##### Implementation example
-
-The following example demonstrates cache key generation using a hash of JSON-encoded parameters.
-
-```php
-class MyCacheKeyGenerator implements CacheKeyGenerator
-{
-    public function generateCacheKey($source, array $sortedOptions)
-    {
-        return md5(json_encode([$source, $optionsSorted]));
-    }
-}
-```
-
 ---
 
 <div align="center">
@@ -273,7 +245,7 @@ INTERMISSION
 
 Congratulations! We have covered everything needed to use Porter.
 
-The rest of this readme is for those wishing to go deeper. Continue when you're ready to learn how to write [providers](#providers), [resources](#resources) and [connectors](#connectors).
+The rest of this readme is for those wishing to go deeper. Continue when you're ready to learn how to write [providers](#providers), [resources](#resources) and [connectors](#connectors). ☕️
 
 </div>
 
@@ -328,8 +300,8 @@ Resources
 Resources fetch data using the supplied connector and format it as a collection of arrays. A resource implements `ProviderResource` that defines the following three methods.
 
 ```php
-public function getProviderClassName() : string;
-public function fetch(ImportConnector $connector) : Iterator;
+public function getProviderClassName(): string;
+public function fetch(ImportConnector $connector): Iterator;
 ```
 
 A resource supplies the class name of the provider it expects a connector from when `getProviderClassName()` is called.
@@ -447,7 +419,7 @@ Connectors fetch remote data from a source specified at fetch time. Connectors f
 Writing providers and resources is a common task that should be fairly easy but writing a connector is slightly less common and has some specific technical considerations that must be carefully considered. A connector implements the `Connector` interface that defines one method with the following signature.
 
 ```php
-public function fetch(ConnectionContext $context, $source) : mixed;
+public function fetch(ConnectionContext $context, $source): mixed;
 ```
 
 When `fetch()` is called the connector fetches data from the specified source. Connectors may return data in any format that's convenient for resources to consume, but in general, such data should be as raw as possible and without modification. If multiple pieces of information are returned it is recommended to use a specialized response class, like the HTTP connector that returns the response body and headers together in an `HttpResponse`.

docs/Quickstart.md

@@ -1,3 +1,6 @@
+Porter Quick Start Guide
+========================
+
 This quick start guide will walk through getting up and running with Porter from scratch and assumes you already have a PHP environment set up with Composer. Let's start by initializing our Composer file by running `composer init` in our project's root directory and accepting the defaults. We can skip defining dependencies interactively because we'll issue separate commands in  a moment.
 
 Let's start with the [European Central Bank][ECB provider] (ECB) provider by including it in our `composer.json` with the following command.