osMetricStat
	osMetricAccess
	osMetricCreate
	osMetricReadDirent
	osMetricFdatasync
	osMetricSync

	// .... add more

	osMetricLast
)

var globalOSMetrics osMetrics

func init() {
	// Inject metrics.
	ioutilx.OsOpenFile = OpenFile
	ioutilx.OpenFileDirectIO = OpenFileDirectIO
	ioutilx.OsOpen = Open
}

type osMetrics struct {
	// All fields must be accessed atomically and aligned.

* شیوه `http`: سیستم‌های استاندارد احراز هویت HTTP، از جمله:
    * مقدار `bearer`: یک هدر `Authorization` با مقدار `Bearer` به همراه یک توکن. این از OAuth2 به ارث برده شده است.
    * احراز هویت پایه HTTP.
    * ویژگی HTTP Digest و غیره.
* شیوه `oauth2`: تمام روش‌های OAuth2 برای مدیریت امنیت (به نام "flows").
    * چندین از این flows برای ساخت یک ارائه‌دهنده احراز هویت OAuth 2.0 مناسب هستند (مانند گوگل، فیسبوک، توییتر، گیت‌هاب و غیره):

        // Mock the request buffer
        DfsReferralRequestBuffer mockRequest = mock(DfsReferralRequestBuffer.class);
        when(mockRequest.encode(any(byte[].class), anyInt())).thenReturn(10);

        // Inject mock request
        Field requestField = Trans2GetDfsReferral.class.getDeclaredField("request");
        requestField.setAccessible(true);
        requestField.set(trans2GetDfsReferral, mockRequest);

        }

        @Override
        public int encode(byte[] dst, int dstIndex) {
            return 0;
        }

        @Override
        public void setDigest(SMBSigningDigest digest) {
        }

        @Override
        public SMBSigningDigest getDigest() {
            return null;
        }

        @Override
        public CommonServerMessageBlockResponse getResponse() {

            byte[] hash = md.digest(input);
            System.arraycopy(hash, 0, derived, 0, Math.min(length, hash.length));

            // If we need more bytes, hash again with counter
            int counter = 1;
            while (derived.length > hash.length * counter) {
                md.update(input);
                md.update((byte) counter);
                hash = md.digest();

                        badWord.setSuggestWord(targetWord);
                        badWord.setCreatedBy(Constants.SYSTEM_USER);
                        badWord.setCreatedTime(now);
                        badWordBhv.insert(badWord);
                    } else {
                        badWord.setUpdatedBy(Constants.SYSTEM_USER);
                        badWord.setUpdatedTime(now);
                        badWordBhv.update(badWord);

      System.setProperty("javax.net.debug", "")
      logger =
        Logger
          .getLogger("javax.net.ssl")
          .apply {
            level = Level.FINEST
            useParentHandlers = false
          }
    }
  }
}

@SuppressSignatureCheck
class WiresharkExample(
  tlsVersions: List<TlsVersion>,
  private val launch: Launch? = null,
) {

		},
		{
			"name":    "dog",
			"user_id": gorm.Expr("@uid"),
		},
	})

	if !regexp.MustCompile(`INSERT INTO .pets. \(.name.,.user_id.\) .*VALUES \(.+,\(SELECT @uid:=id FROM \(SELECT id FROM .users. WHERE name=.+\) as tmp\)\),\(.+,@uid\)`).MatchString(result.Statement.SQL.String()) {
		t.Errorf("invalid insert SQL, got %v", result.Statement.SQL.String())
	}
}

func TestCreateNilPointer(t *testing.T) {
	var user *User

	// create
	user := &User{Name: "foo", Age: 20}
	user.CreatedAt = date
	user.UpdatedAt = date
	sql = DB.ToSQL(func(tx *gorm.DB) *gorm.DB {
		return tx.Model(&User{}).Create(user)
	})
	assertEqualSQL(t, `INSERT INTO "users" ("created_at","updated_at","deleted_at","name","age","birthday","company_id","manager_id","active") VALUES ('2021-10-18 00:00:00','2021-10-18 00:00:00',NULL,'foo',20,NULL,NULL,NULL,false) RETURNING "id"`, sql)

	// save

And then, that system (in this case **FastAPI**) will take care of doing whatever is needed to provide your code with those needed dependencies ("inject" the dependencies).

This is very useful when you need to:

* Have shared logic (the same code logic again and again).
* Share database connections.
* Enforce security, authentication, role requirements, etc.