import ( "github.com/apache/thrift/lib/go/thrift" "io" ) func WriteThriftMessage(p thrift.TProtocol, w io.Writer, methodName string) error { // Write the message header if err := p.WriteMessageBegin(methodName, thrift.CALL, 0); err != nil { return err } // Write the message payload here ... // Write the message footer if err := p.WriteMessageEnd(); err != nil { return err } // Flush the output stream if err := p.Transport().Flush(); err != nil { return err } return nil }In this example, we create a function called `WriteThriftMessage` that takes a TProtocol instance, an output stream, and a method name as parameters. We use the `WriteMessageBegin` method to write the message header to the output stream, with the method name set to the value passed as a parameter, and the message type set to `thrift.CALL`. We then write the message payload, and write the message footer using the `WriteMessageEnd` method. This example demonstrates how the `WriteMessageBegin` method can be used to write the beginning of a Thrift message, and is part of the go.github.com.apache.thrift.lib.go.thrift TProtocol package.