Update: architecture.md for merge server (#1520)

ARCHITECTURE.md

@@ -7,17 +7,26 @@ This extension contains three major components:
 
 # Gradle Server and Gradle Language Server
 
-<img src="images/gradle-tasks-architecture.svg" />
+<img src="images/gradle-server-architecture.svg" />
+The gradle server is a long-running Java process that include two threads: 1. Build Server 2. Task Server
 
-The extension uses client/server architecture using [gRPC](https://grpc.io/) as the interface between the client and server. It uses TypeScript (Node.js) on the client and Java on the server. A long running server provides very good performance.
+## Build Server
+The Gradle Build Server communicates with the Build Client using the [Build Server Protocol](https://build-server-protocol.github.io/) through named pipes.
+
+Due to Java's limited support for named pipes on Windows, a TypeScript layer named [BspProxy](./extension/src/bs/BspProxy.ts) was introduced. This layer acts as a middleware and it helps by sending messages back and forth and creating a safer named pipe JSON-RPC connection between the Gradle Build Server and the Build Client.
+
+For information about the Build Server itself, visit the [Gradle Build Server](https://github.com/microsoft/build-server-for-gradle).
+
+## Task Server
+The task server and client using [gRPC](https://grpc.io/) as the interface between each other. It uses TypeScript (Node.js) on the client and Java on the server. A long running server provides very good performance.
 
 On extension activate, the client starts the Java gRPC server which remains running for the period the extension is activated. The server is packaged with the extension as a fat `.jar` file and is started by Node.js via executables generated by Gradle [CreateStartScripts](https://docs.gradle.org/current/dsl/org.gradle.jvm.application.tasks.CreateStartScripts.html).
 
 [Protocol buffers](https://developers.google.com/protocol-buffers) are used to define the gRPC service & messages. The Java & JavaScript message classes, as well as the client and server interfaces, are generated from the Protobuf files via the `protoc` compiler. TypeScript type definitions are generated from the JavaScript classes.
 
 The Java server uses the [Gradle Tooling Api](https://docs.gradle.org/current/userguide/third_party_integration.html#embedding) to discover projects & tasks, and to run Gradle tasks.
 
-## Discovering Projects & Tasks
+### Discovering Projects & Tasks
 
 Tasks belong to projects and projects are hierarchical, meaning projects can have sub-projects, and any/all projects in the tree can have tasks.
 
@@ -29,7 +38,7 @@ Once the client has discovered the root projects for all workspaces, it requests
 
 The extension models the project hierarchical structure using the vscode tree view. The tree view data provider consumes the vscode tasks, and builds a tree of projects & tasks using the information provided in the task definitions.
 
-## Running Tasks
+### Running Tasks
 
 Gradle tasks can be run through either the [Tree View](https://code.visualstudio.com/api/extension-guides/tree-view) or the Command Palette.
 
@@ -41,6 +50,6 @@ Gradle is used as the build system for the extension, for both the client and th
 
 Getting started on this extension is as simple as `./gradlew build`.
 
-## Gradle Project Importer
+# Gradle Project Importer
 
 The Gradle project importer works as a client of the [Gradle Build Server](https://github.com/microsoft/build-server-for-gradle). The importer communicates with the Gradle build server via Build Server Protocol, and convert the build targets into Java Projects of JDT Language Server.