doc: set random seed in `init_worker` phase. (#52)

* doc: set random seed in `init_worker` phase.

try to fix issue: https://github.com/apache/skywalking/issues/5805 .

* e2e: set random seed.
diff --git a/README.md b/README.md
index 9e69551..1ec2a4e 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,8 @@
         -- Instance means the number of Nginx deployment, does not mean the worker instances
         metadata_buffer:set('serviceInstanceName', 'User Service Instance Name')
 
+        -- set random seed
+        require("skywalking.util").set_randomseed()
         require("skywalking.client"):startBackendTimer("http://127.0.0.1:8080")
     }
 
diff --git a/examples/nginx.conf b/examples/nginx.conf
index b9a74bf..db613a2 100644
--- a/examples/nginx.conf
+++ b/examples/nginx.conf
@@ -38,6 +38,7 @@
         -- Instance means the number of Nginx deloyment, does not mean the worker instances
         metadata_buffer:set('serviceInstanceName', 'User Service Instance Name')
 
+        require("skywalking.util").set_randomseed()
         require("skywalking.client"):startBackendTimer("http://127.0.0.1:8080")
     }
 
diff --git a/test/e2e/e2e-with-mock-collector/docker/conf.d/nginx.conf b/test/e2e/e2e-with-mock-collector/docker/conf.d/nginx.conf
index d7ef21f..cd1e679 100644
--- a/test/e2e/e2e-with-mock-collector/docker/conf.d/nginx.conf
+++ b/test/e2e/e2e-with-mock-collector/docker/conf.d/nginx.conf
@@ -38,6 +38,7 @@
         -- Instance means the number of Nginx deployment, does not mean the worker instances
         metadata_buffer:set('serviceInstanceName', 'e2e-test-with-mock-collector-instanceA')
 
+        require("skywalking.util").set_randomseed()
         require("skywalking.client"):startBackendTimer("http://${collector}:12800")
     }