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To start work, create an instance of TelegramClient and establish connection
```csharp
var client = new TelegramClient(apiId, apiHash);
await client.ConnectAsync();
```
Now you can work with Telegram API, but ->
> Only a small portion of the API methods are available to unauthorized users. ([full description](https://core.telegram.org/api/auth))
For authentication you need to run following code
```csharp
var hash = await client.SendCodeRequestAsync("<user_number>");
var code = "<code_from_telegram>"; // you can change code in debugger
var user = await client.MakeAuthAsync("<user_number>", hash, code);
```
Full code you can see at [AuthUser test](https://github.com/sochix/TLSharp/blob/master/TLSharp.Tests/TLSharpTests.cs#L70)
When user is authenticated, TLSharp creates special file called _session.dat_. In this file TLSharp store all information needed for user session. So you need to authenticate user every time the _session.dat_ file is corrupted or removed.
You can call any method on authenticated user. For example, let's send message to a friend by his phone number:
Telegram separate files to two categories -> big file and small file. File is Big if its size more than 10 Mb. TLSharp tries to hide this complexity from you, thats why we provide one method to upload files **UploadFile**.
new TLVector<TLAbsDocumentAttribute>()); //document attributes, such as file name
```
Full code you can see at [SendPhotoToContactTest](https://github.com/sochix/TLSharp/blob/master/TLSharp.Tests/TLSharpTests.cs#L125) and [SendBigFileToContactTest](https://github.com/sochix/TLSharp/blob/master/TLSharp.Tests/TLSharpTests.cs#L143)
To download file you should call **GetFile** method
```csharp
await client.GetFile(
new TLInputDocumentFileLocation()
{
access_hash = document.access_hash,
id = document.id,
version = document.version
},
document.size); //size of fileChunk you want to retrieve
```
Full code you can see at [DownloadFileFromContactTest](https://github.com/sochix/TLSharp/blob/master/TLSharp.Tests/TLSharpTests.cs#L167)
TLSharp library should automatically handle these errors. If you see such errors, please open a new Github issue with the details (include a stacktrace, etc.).
#### I get an exception: System.IO.EndOfStreamException: Unable to read beyond the end of the stream. All test methos except that AuthenticationWorks and TestConnection return same error. I did every thing including setting api id and hash, and setting server address.-
#### Why do I get a FloodException/FLOOD_WAIT error?
It's likely [Telegram restrictions](https://core.telegram.org/api/errors#420-flood), or a bug in TLSharp (if you feel it's the latter, please open a Github issue). You can know the time to wait by accessing the FloodException::TimeToWait property.
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