Improve import time by lazy-loading cloud provider modules

[eh-steve]

Title

Improve import time by lazy-loading cloud provider modules

Description

Problem

Importing cloudpathlib currently takes ~435ms because it eagerly loads all cloud provider SDKs (google-cloud-storage, boto3, azure-storage-blob) at import time, even if the user only needs one provider.

This is problematic for:

• CLI tools where startup latency matters
• Serverless functions where cold start time is critical
• Applications that only use one cloud provider but pay the import cost for all three

Benchmarks

Measured with Python 3.12 (5 runs, mean ± std):

Scenario	Current	With Lazy Loading	Improvement
import cloudpathlib	435ms ± 24ms	22ms ± 1ms	95% faster
from cloudpathlib import S3Path	410ms ± 3ms	23ms ± 0ms	94% faster
from cloudpathlib import GSPath	410ms ± 3ms	24ms ± 1ms	94% faster
from cloudpathlib import AzureBlobPath	413ms ± 7ms	41ms ± 1ms	90% faster

Additionally, the current implementation loads all three SDKs even when importing just one path class. With lazy loading, only the SDK for the provider being used gets loaded.

Proposed Solution

Implement lazy loading via __getattr__ in the __init__.py files:

• cloudpathlib/__init__.py
• cloudpathlib/s3/__init__.py
• cloudpathlib/gs/__init__.py
• cloudpathlib/azure/__init__.py

This defers loading cloud SDKs until they are actually accessed, while preserving static type hints via TYPE_CHECKING blocks.

Example

Before:
import cloudpathlib # Takes ~435ms, loads all SDKsAfter:
import cloudpathlib # Takes ~22ms, no SDKs loaded
from cloudpathlib import S3Path # Only loads boto3 when S3Path is accessed

Implementation Notes

• Use __getattr__ with TYPE_CHECKING blocks for static type hints (IDE support preserved)
• Fix absolute import in cloudpath.py (from cloudpathlib.enums → from .enums)
• Move anypath import to function-local in cloudpath.py to avoid circular imports
• Add tests to verify lazy loading behavior and prevent regressions

I have a working implementation ready to submit as a PR.