switch to 'cross-fetch' instead of 'request' (#6)

* Replaces `request` with `cross-fetch`, and isomorphic fetch library
  - The `RequestOptions` type is a mix of the browser and `node-fetch` options, so that server-side code can set things like the `agent` for keepalive, but it should have no effect in browser code
  - The `lodash` dependency was removed from the `thrift-server-core` library, because all it was used for was doing "deep merges" on the client, which weren't needed. Instead, a new function to merge together request options was added, with special logic for the `Headers` values (which can't utilize object spread).
  - The `response.arrayBuffer()` function is used to get an `ArrayBuffer` and convert the binary response into a Node `Buffer`, which is what the generated code expects to use when sending requests through the connection. We'll need to polyfill that with Webpack, but it should be just fine.
* Removed all uses of the `url.parse` and `url.format` deprecated functions and replaced them with the WHATWG URL API
* Fixed a number of tests and cleaned them up with the right response types

packages/thrift-client-zipkin-filter/package.json

@@ -44,8 +44,7 @@
         "typescript": "~4.4.4"
     },
     "dependencies": {
-        "@types/request": "^2.48.8",
-        "request": "^2.88.2",
+        "cross-fetch": "^3.1.4",
         "zipkin": "^0.22.0"
     }
 }

packages/thrift-client-zipkin-filter/src/main/ThriftClientZipkinFilter.ts

@@ -1,7 +1,5 @@
 import { Instrumentation, TraceId, Tracer } from 'zipkin'
 
-import { CoreOptions } from 'request'
-
 import {
     formatUrl,
     IRequestContext,
@@ -15,6 +13,7 @@ import {
     IThriftClientFilter,
     IThriftRequest,
     NextFunction,
+    RequestOptions,
 } from '@statestitle/thrift-client'
 
 import {
@@ -65,7 +64,7 @@ function readRequestContext(
 }
 
 function readRequestHeaders(
-    request: IThriftRequest<CoreOptions>,
+    request: IThriftRequest<RequestOptions>,
 ): IRequestHeaders {
     if (request.context && request.context.headers) {
         return request.context.headers
@@ -78,7 +77,7 @@ export function ThriftClientZipkinFilter<Context extends IRequest>({
     localServiceName,
     remoteServiceName,
     tracerConfig = {},
-}: IZipkinClientOptions): IThriftClientFilter<CoreOptions> {
+}: IZipkinClientOptions): IThriftClientFilter<RequestOptions> {
     const serviceName: string = remoteServiceName || localServiceName
     const tracer: Tracer = getTracerForService(serviceName, tracerConfig)
     const instrumentation = new Instrumentation.HttpClient({
@@ -90,8 +89,8 @@ export function ThriftClientZipkinFilter<Context extends IRequest>({
     return {
         methods: [],
         handler(
-            request: IThriftRequest<CoreOptions>,
-            next: NextFunction<CoreOptions>,
+            request: IThriftRequest<RequestOptions>,
+            next: NextFunction<RequestOptions>,
         ): Promise<IRequestResponse> {
             const requestHeaders: IRequestHeaders = readRequestHeaders(request)
             const requestContext: IRequestContext = readRequestContext(