fix: a possible race condition that we used table schema out of the lock. (#1575)

Also clean up the code to reconnect after 10MB.

Author: yirutang

google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/JsonStreamWriter.java

@@ -134,41 +134,21 @@ public ApiFuture<AppendRowsResponse> append(JSONArray jsonArr, long offset)
         // Create a new underlying StreamWriter with the updated TableSchema and Descriptor
         this.streamWriter = streamWriterBuilder.setWriterSchema(this.protoSchema).build();
       }
-    }
 
-    ProtoRows.Builder rowsBuilder = ProtoRows.newBuilder();
-    // Any error in convertJsonToProtoMessage will throw an
-    // IllegalArgumentException/IllegalStateException/NullPointerException and will halt processing
-    // of JSON data.
-    long currentRequestSize = 0;
-    for (int i = 0; i < jsonArr.length(); i++) {
-      JSONObject json = jsonArr.getJSONObject(i);
-      Message protoMessage =
-          JsonToProtoMessage.convertJsonToProtoMessage(
-              this.descriptor, this.tableSchema, json, ignoreUnknownFields);
-      rowsBuilder.addSerializedRows(protoMessage.toByteString());
-      currentRequestSize += protoMessage.getSerializedSize();
-    }
-    // Need to make sure refreshAppendAndSetDescriptor finish first before this can run
-    synchronized (this) {
-      this.totalMessageSize += currentRequestSize;
-      this.absTotal += currentRequestSize;
-      // Reconnect on every 9.5MB.
-      if (this.totalMessageSize > 9500000 && this.reconnectAfter10M) {
-        streamWriter.close();
-        // Create a new underlying StreamWriter aka establish a new connection.
-        this.streamWriter = streamWriterBuilder.setWriterSchema(protoSchema).build();
-        this.totalMessageSize = this.protoSchema.getSerializedSize() + currentRequestSize;
-        this.absTotal += currentRequestSize;
-        // Allow first request to pass.
+      ProtoRows.Builder rowsBuilder = ProtoRows.newBuilder();
+      // Any error in convertJsonToProtoMessage will throw an
+      // IllegalArgumentException/IllegalStateException/NullPointerException and will halt
+      // processing
+      // of JSON data.
+      long currentRequestSize = 0;
+      for (int i = 0; i < jsonArr.length(); i++) {
+        JSONObject json = jsonArr.getJSONObject(i);
+        Message protoMessage =
+            JsonToProtoMessage.convertJsonToProtoMessage(
+                this.descriptor, this.tableSchema, json, ignoreUnknownFields);
+        rowsBuilder.addSerializedRows(protoMessage.toByteString());
+        currentRequestSize += protoMessage.getSerializedSize();
       }
-      LOG.fine(
-          "Sending a total of:"
-              + this.totalMessageSize
-              + " "
-              + currentRequestSize
-              + " "
-              + this.absTotal);
       final ApiFuture<AppendRowsResponse> appendResponseFuture =
           this.streamWriter.append(rowsBuilder.build(), offset);
       return appendResponseFuture;