## Change Summary

This means `pydantic/__init__.py` is now lazy about all imports using `__getattr__`.

Import performance changes:
### Before

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 29.7 msec per loop
```

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"
1 loop, best of 1: 30.4 msec per loop
```

### After

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 4.8 msec per loop
```

```
(env3112) code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"           
1 loop, best of 1: 18.7 msec per loop
```

Tuna output:

<img width="1421" alt="image" src="https://github.com/pydantic/pydantic/assets/4039449/0a57434e-fdda-4709-8793-d96c0a0ee762">

## Related issue number

As promised in https://github.com/pydantic/pydantic/pull/7423#issuecomment-1733361629.

## Checklist

* [x] The pull request title is a good summary of the changes - it will be used in the changelog
* [ ] Unit tests for the changes exist
* [x] Tests pass on CI
* [ ] Documentation reflects the changes where applicable
* [x] My PR is ready to review, **please add a comment including the phrase "please review" to assign reviewers**


Selected Reviewer: @sydney-runkle
Use `__getattr__` for all package imports, improve import time. ## Change Summary

This means `pydantic/__init__.py` is now lazy about all imports using `__getattr__`.

Import performance changes:
### Before

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 29.7 msec per loop
```

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"
1 loop, best of 1: 30.4 msec per loop
```

### After

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 4.8 msec per loop
```

```
(env3112) code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"           
1 loop, best of 1: 18.7 msec per loop
```

Tuna output:

<img width="1421" alt="image" src="https://github.com/pydantic/pydantic/assets/4039449/0a57434e-fdda-4709-8793-d96c0a0ee762">

## Related issue number

As promised in https://github.com/pydantic/pydantic/pull/7423#issuecomment-1733361629.

## Checklist

* [x] The pull request title is a good summary of the changes - it will be used in the changelog
* [ ] Unit tests for the changes exist
* [x] Tests pass on CI
* [ ] Documentation reflects the changes where applicable
* [x] My PR is ready to review, **please add a comment including the phrase "please review" to assign reviewers**


Selected Reviewer: @sydney-runkle
!!! warning "🚧 Work in Progress"
    This page is a work in progress.

## Serialize `SecretStr` and `SecretBytes` as plain-text

By default, [`SecretStr`][pydantic.types.SecretStr] and [`SecretBytes`][pydantic.types.SecretBytes]
will be serialized as `**********` when serializing to json.

You can use the [`field_serializer`][pydantic.functional_serializers.field_serializer] to dump the
secret as plain-text when serializing to json.

```py
from pydantic import BaseModel, SecretBytes, SecretStr, field_serializer


class Model(BaseModel):
    password: SecretStr
    password_bytes: SecretBytes

    @field_serializer('password', 'password_bytes', when_used='json')
    def dump_secret(self, v):
        return v.get_secret_value()


model = Model(password='IAmSensitive', password_bytes=b'IAmSensitiveBytes')
print(model)
#> password=SecretStr('**********') password_bytes=SecretBytes(b'**********')
print(model.password)
#> **********
print(model.model_dump())
"""
{
    'password': SecretStr('**********'),
    'password_bytes': SecretBytes(b'**********'),
}
"""
print(model.model_dump_json())
#> {"password":"IAmSensitive","password_bytes":"IAmSensitiveBytes"}
```

!!! warning "🚧 Work in Progress"
    This page is a work in progress.

## Serialize `SecretStr` and `SecretBytes` as plain-text

By default, [`SecretStr`][pydantic.types.SecretStr] and [`SecretBytes`][pydantic.types.SecretBytes]
will be serialized as `**********` when serializing to json.

You can use the [`field_serializer`][pydantic.functional_serializers.field_serializer] to dump the
secret as plain-text when serializing to json.

```py
from pydantic import BaseModel, SecretBytes, SecretStr, field_serializer


class Model(BaseModel):
    password: SecretStr
    password_bytes: SecretBytes

    @field_serializer('password', 'password_bytes', when_used='json')
    def dump_secret(self, v):
        return v.get_secret_value()


model = Model(password='IAmSensitive', password_bytes=b'IAmSensitiveBytes')
print(model)
#> password=SecretStr('**********') password_bytes=SecretBytes(b'**********')
print(model.password)
#> **********
print(model.model_dump())
"""
{
    'password': SecretStr('**********'),
    'password_bytes': SecretBytes(b'**********'),
}
"""
print(model.model_dump_json())
#> {"password":"IAmSensitive","password_bytes":"IAmSensitiveBytes"}
```
