import ( "git.apache.org/thrift.git/lib/go/thrift" ) func writeMyStruct(output thrift.TProtocol, myStruct *MyStruct) error { err := output.WriteStructBegin("MyStruct") if err != nil { return err } err = output.WriteFieldBegin("myField", thrift.STRING, 1) if err != nil { return err } err = output.WriteString(myStruct.myField) if err != nil { return err } err = output.WriteFieldEnd() if err != nil { return err } err := output.WriteStructEnd() if err != nil { return err } return nil }In this example, the function `writeMyStruct` takes as input a `thrift.TProtocol` and a pointer to a user-defined `MyStruct`. It then uses `output.WriteFieldBegin()` to write the beginning of the "myField" field in the protocol buffer with Thrift type `STRING`. This is followed by writing the actual field value using `output.WriteString()`. Finally, `output.WriteFieldEnd()` is called to signal the end of the field, and `output.WriteStructEnd()` is called to signal the end of the struct. Any errors encountered are returned by the function. Overall, `TProtocol.WriteFieldBegin()` is a useful method for writing Thrift protocol buffers in Go.