You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: context.rs
    path of file: ./repos/rerun/crates/re_renderer/src
    
    the code of the file until where you have to start completion: use std::sync::{
    atomic::{AtomicU64, Ordering},
    Arc,
};

use parking_lot::{MappedRwLockReadGuard, Mutex, RwLock, RwLockReadGuard};
use type_map::concurrent::{self, TypeMap};

use crate::{
    allocator::{CpuWriteGpuReadBelt, GpuReadbackBelt},
    config::{DeviceTier, RenderContextConfig},
    error_handling::{ErrorTracker, Wg
    
    pub fn begin_frame(&mut self) {
        re_tracing::profile_function!();

        // If the currently active frame still has an encoder, we need to finish it and queue it.
        // This should only ever happen for the first frame where we created an encoder for preparatory work. Every other frame we take the encoder at submit!
        if self
            .active_frame
            .before_view_builder_encoder
            .lock()
            .0
            .is_some()
        {
            if self.active_frame.frame_index != STARTUP_FRAME_IDX {
                re_log::error!("There was still a command encoder from the previous frame at the beginning of the current.
This means, either a call to RenderContext::before_submit was omitted, or the previous frame was unexpectedly cancelled.");
            }
            self.before_submit();
        }

        // Request write used staging buffer back.
        // TODO(andreas): If we'd control all submissions, we could move this directly after the submission which would be a bit better.
        self.cpu_write_gpu_read_belt.get_mut().after_queue_submit();
        // Map all read staging buffers.
        self.gpu_readback_belt.get_mut().after_queue_submit();

        // Give back moved render pipelines to the pool if any were moved out.
        if let Some(moved_render_pipelines) = self.active_frame.pinned_render_pipelines.take() {
            self.gpu_resources
                .render_pipelines
                .return_resources(moved_render_pipelines);
        }

        // Close previous' frame error scope.
        if let Some(top_level_error_scope) = self.active_frame.top_level_error_scope.take() {
            let frame_index_for_uncaptured_errors = self.frame_index_for_uncaptured_errors.clone();
            self.top_level_error_tracker.handle_error_future(
                self.config.device_caps.backend_type,
                top_level_error_scope.end(),
                self.active_frame.frame_index,
                move |err_tracker, frame_index| {
                    // Update last completed frame index.
                    //
                    // Note that this means that the device timeline has now finished this frame as well!
                    // Reminder: On WebGPU the device timeline may be arbitrarily behind the content timeline!
                    // See <https://www.w3.org/TR/webgpu/#programming-model-timelines>.
                    frame_index_for_uncaptured_errors.store(frame_index, Ordering::Release);
                    err_tracker.on_device_timeline_frame_finished(frame_index);

                    // TODO(#4507): Once we support creating more error handlers,
                    // we need to tell all of them here that the frame has finished.
                },
            );
        }

        // New active frame!
        self.active_frame = ActiveFrameContext {
            before_view_builder_encoder: Mutex::new(FrameGlobalCommandEncoder::new(&self.device)),
            pinned_render_pipelines: None,
            frame_index: self.active_frame.frame_index.wrapping_add(1),
            top_level_error_scope: Some(WgpuErrorScope::start(&self.device)),
        };
        let frame_index = self.active_frame.frame_index;

        // The set of files on disk that were modified in any way since last frame,
        // ignoring deletions.
        // Always an empty set in release builds.
        let modified_paths = FileServer::get_mut(|fs| fs.collect(&self.resolver));
        if !modified_paths.is_empty() {
            re_log::debug!(?modified_paths, "got some filesystem events");
        }

        self.mesh_manager.get_mut().begin_frame(frame_index);
        self.texture_manager_2d.begin_frame(frame_index);
        self.gpu_readback_belt.get_mut().begin_frame(frame_index);

        {
            let WgpuResourcePools {
                bind_group_layouts,
                bind_groups,
                pipeline_layouts,
                render_pipelines,
                samplers,
                shader_modules,
                textures,
                buffers,
            } = &mut self.gpu_resources; // not all pools require maintenance

            // Shader module maintenance must come before render pipelines because render pipeline
            // recompilation picks up all shaders that have been recompiled this frame.
            shader_modules.begin_frame(&self.device, &self.resolver, frame_index, &modified_paths);
            render_pipelines.begin_frame(
                &self.device,
                frame_index,
                shader_modules,
                pipeline_layouts,
            );

            bind_groups.begin_frame(frame_index, textures, buffers, samplers);

            textures.begin_frame(frame_index);
            buffers.begin_frame(frame_index);

            pipeline_layouts.begin_frame(frame_index);
            bind_group_layouts.begin_frame(frame_index);
            samplers.begin_frame(frame_index);
        }

        // Poll device *after* resource pool `begin_frame` since resource pools may each decide drop resources.
        // Wgpu internally may then internally decide to let go of these buffers.
        self.poll_device();
    }