# FixIO Documentation

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`import "io/tcp";`

## AsyncTCPConnection class

Asynchronous TCP connection.

Inherits from AsyncStream.

### Functions

`static function open(hostname: String, port: Integer, callback, data): AsyncTCPConnection`
  Initiates connecting to given host and port. Once finished the callback is called. The callback must have this signature:
  `function callback(data, conn: AsyncTCPConnection)`
  The `conn` parameter provides the established connection or `null` in case there was an error.