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: config.rs
    path of file: ./repos/bee/bee-storage/bee-storage-rocksdb/src
    
    the code of the file until where you have to start completion: // Copyright 2020-2021 IOTA Stiftung
// SPDX-License-Identifier: Apache-2.0

use std::path::PathBuf;

use serde::Deserialize;

use crate::{compaction::CompactionStyle, compression::CompressionType};

const DEFAULT_FETCH_EDGE_LIMIT: usize = 1_000;
const DEFAULT_FETCH_OUTPUT_ID_LIMIT: usize = 1_000;

const DEFAULT_PATH: &str = "./storage/mainnet/tangle";
const DEFAULT_CREATE_IF_MISSING: bool = true;
const DEFAULT_CREATE_MISSING_COLUMN_FAMILIES: bool = true;
const DEFAULT_ENABLE_STATISTICS: bool = false;
const DEFAULT_OPTIMIZE_FOR_POINT_LOOKUP: u64 = 67_108_864; // 64 MiB
const DEFAULT_OPTIMIZE_LEVEL_STYLE_COMPACTION: usize = 0;
const DEFAULT_OPTIMIZE_UNIVERSAL_STYLE_COMPACTION: usize = 0;
const DEFAULT_SET_ADVISE_RANDOM_ON_OPEN: b
    
    fn from(builder: RocksDbConfigBuilder) -> Self {
        RocksDbConfig {
            storage: builder.storage.unwrap_or_default().finish(),
            path: PathBuf::from(builder.path.unwrap_or_else(|| DEFAULT_PATH.to_string())),
            create_if_missing: builder.create_if_missing.unwrap_or(DEFAULT_CREATE_IF_MISSING),
            create_missing_column_families: builder
                .create_missing_column_families
                .unwrap_or(DEFAULT_CREATE_MISSING_COLUMN_FAMILIES),
            enable_statistics: builder.enable_statistics.unwrap_or(DEFAULT_ENABLE_STATISTICS),
            increase_parallelism: builder.increase_parallelism.unwrap_or(num_cpus::get() as i32),
            optimize_for_point_lookup: builder
                .optimize_for_point_lookup
                .unwrap_or(DEFAULT_OPTIMIZE_FOR_POINT_LOOKUP),
            optimize_level_style_compaction: builder
                .optimize_level_style_compaction
                .unwrap_or(DEFAULT_OPTIMIZE_LEVEL_STYLE_COMPACTION),
            optimize_universal_style_compaction: builder
                .optimize_universal_style_compaction
                .unwrap_or(DEFAULT_OPTIMIZE_UNIVERSAL_STYLE_COMPACTION),
            set_advise_random_on_open: builder
                .set_advise_random_on_open
                .unwrap_or(DEFAULT_SET_ADVISE_RANDOM_ON_OPEN),
            set_allow_concurrent_memtable_write: builder
                .set_allow_concurrent_memtable_write
                .unwrap_or(DEFAULT_SET_ALLOW_CONCURRENT_MEMTABLE_WRITE),
            set_allow_mmap_reads: builder.set_allow_mmap_reads.unwrap_or(DEFAULT_SET_ALLOW_MMAP_READS),
            set_allow_mmap_writes: builder.set_allow_mmap_writes.unwrap_or(DEFAULT_SET_ALLOW_MMAP_WRITES),
            set_atomic_flush: builder.set_atomic_flush.unwrap_or(DEFAULT_SET_ATOMIC_FLUSH),
            set_bytes_per_sync: builder.set_bytes_per_sync.unwrap_or(DEFAULT_SET_BYTES_PER_SYNC),
            set_compaction_readahead_size: builder
                .set_compaction_readahead_size
                .unwrap_or(DEFAULT_SET_COMPACTION_READAHEAD_SIZE),
            set_compaction_style: builder.set_compaction_style.unwrap_or(DEFAULT_SET_COMPACTION_STYLE),
            set_max_write_buffer_number: builder
                .set_max_write_buffer_number
                .unwrap_or(DEFAULT_SET_MAX_WRITE_BUFFER_NUMBER),
            set_write_buffer_size: builder.set_write_buffer_size.unwrap_or(DEFAULT_SET_WRITE_BUFFER_SIZE),
            set_db_write_buffer_size: builder
                .set_db_write_buffer_size
                .unwrap_or(DEFAULT_SET_DB_WRITE_BUFFER_SIZE),
            set_disable_auto_compactions: builder
                .set_disable_auto_compactions
                .unwrap_or(DEFAULT_SET_DISABLE_AUTO_COMPACTIONS),
            set_compression_type: builder.set_compression_type.unwrap_or(DEFAULT_SET_COMPRESSION_TYPE),
            set_unordered_write: builder.set_unordered_write.unwrap_or(DEFAULT_SET_UNORDERED_WRITE),
            set_use_direct_io_for_flush_and_compaction: builder
                .set_use_direct_io_for_flush_and_compaction
                .unwrap_or(DEFAULT_SET_USE_DIRECT_IO_FOR_FLUSH_AND_COMPACTION),
            env: builder.env.unwrap_or_default().finish(),
        }
    }