Allow users to customize the InitializeParams object for the "initialize" method

src/main/java/org/wso2/lsp4intellij/client/languageserver/serverdefinition/LanguageServerDefinition.java

@@ -18,6 +18,7 @@
 import com.intellij.openapi.diagnostic.Logger;
 import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.apache.commons.lang3.tuple.Pair;
+import org.eclipse.lsp4j.InitializeParams;
 import org.wso2.lsp4intellij.client.connection.StreamConnectionProvider;
 
 import java.io.IOException;
@@ -77,6 +78,15 @@ public void stop(String workingDir) {
     public Object getInitializationOptions(URI uri) {
         return null;
     }
+
+    /**
+     * Use this method to modify the {@link InitializeParams} that was initialized by this library.
+     * The values assigned to the passed {@link InitializeParams} after this method ends will be the 
+     * ones sent to the LSP server.
+     * @param params the parameters with some prefilled values.
+     */
+    public void customizeInitializeParams(InitializeParams params) {
+    }
 
     @Override
     public String toString() {

src/main/java/org/wso2/lsp4intellij/client/languageserver/wrapper/LanguageServerWrapper.java

@@ -588,6 +588,7 @@ private InitializeParams getInitParams() {
                 new ClientCapabilities(workspaceClientCapabilities, textDocumentClientCapabilities, null));
         initParams.setInitializationOptions(
                 serverDefinition.getInitializationOptions(URI.create(initParams.getRootUri())));
+        serverDefinition.customizeInitializeParams(initParams);
 
         return initParams;
     }