http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
public final class io.netty.handler.codec.smtp.SmtpRequestEncoder extends io.netty.handler.codec.MessageToMessageEncoder<java.lang.Object>
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: io.netty.handler.codec.smtp.SmtpRequestEncoder
  super_class: io.netty.handler.codec.MessageToMessageEncoder
{
  private static final int CRLF_SHORT;
    descriptor: I
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 3338

  private static final byte SP;
    descriptor: B
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 32

  private static final io.netty.buffer.ByteBuf DOT_CRLF_BUFFER;
    descriptor: Lio/netty/buffer/ByteBuf;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL

  private boolean contentExpected;
    descriptor: Z
    flags: (0x0002) ACC_PRIVATE

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=0, args_size=0
         0: .line 37
            iconst_3
            invokestatic io.netty.buffer.Unpooled.directBuffer:(I)Lio/netty/buffer/ByteBuf;
            bipush 46
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
            bipush 13
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
            bipush 10
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
         1: .line 36
            invokestatic io.netty.buffer.Unpooled.unreleasableBuffer:(Lio/netty/buffer/ByteBuf;)Lio/netty/buffer/ByteBuf;
            putstatic io.netty.handler.codec.smtp.SmtpRequestEncoder.DOT_CRLF_BUFFER:Lio/netty/buffer/ByteBuf;
         2: .line 37
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
         0: .line 33
            aload 0 /* this */
            invokespecial io.netty.handler.codec.MessageToMessageEncoder.<init>:()V
            return
        end local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/smtp/SmtpRequestEncoder;

  public boolean acceptOutboundMessage(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=2, args_size=2
        start local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
        start local 1 // java.lang.Object msg
         0: .line 43
            aload 1 /* msg */
            instanceof io.netty.handler.codec.smtp.SmtpRequest
            ifne 1
            aload 1 /* msg */
            instanceof io.netty.handler.codec.smtp.SmtpContent
            ifne 1
            iconst_0
            ireturn
      StackMap locals:
      StackMap stack:
         1: iconst_1
            ireturn
        end local 1 // java.lang.Object msg
        end local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lio/netty/handler/codec/smtp/SmtpRequestEncoder;
            0    2     1   msg  Ljava/lang/Object;
    Exceptions:
      throws java.lang.Exception
    MethodParameters:
      Name  Flags
      msg   

  protected void encode(io.netty.channel.ChannelHandlerContext, , java.util.List<java.lang.Object>);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;Ljava/lang/Object;Ljava/util/List;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=3, locals=8, args_size=4
        start local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
        start local 2 // java.lang.Object msg
        start local 3 // java.util.List out
         0: .line 48
            aload 2 /* msg */
            instanceof io.netty.handler.codec.smtp.SmtpRequest
            ifeq 23
         1: .line 49
            aload 2 /* msg */
            checkcast io.netty.handler.codec.smtp.SmtpRequest
            astore 4 /* req */
        start local 4 // io.netty.handler.codec.smtp.SmtpRequest req
         2: .line 50
            aload 0 /* this */
            getfield io.netty.handler.codec.smtp.SmtpRequestEncoder.contentExpected:Z
            ifeq 7
         3: .line 51
            aload 4 /* req */
            invokeinterface io.netty.handler.codec.smtp.SmtpRequest.command:()Lio/netty/handler/codec/smtp/SmtpCommand;
            getstatic io.netty.handler.codec.smtp.SmtpCommand.RSET:Lio/netty/handler/codec/smtp/SmtpCommand;
            invokevirtual io.netty.handler.codec.smtp.SmtpCommand.equals:(Ljava/lang/Object;)Z
            ifeq 6
         4: .line 52
            aload 0 /* this */
            iconst_0
            putfield io.netty.handler.codec.smtp.SmtpRequestEncoder.contentExpected:Z
         5: .line 53
            goto 7
         6: .line 54
      StackMap locals: io.netty.handler.codec.smtp.SmtpRequest
      StackMap stack:
            new java.lang.IllegalStateException
            dup
            ldc "SmtpContent expected"
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
         7: .line 57
      StackMap locals:
      StackMap stack:
            iconst_1
            istore 5 /* release */
        start local 5 // boolean release
         8: .line 58
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.alloc:()Lio/netty/buffer/ByteBufAllocator;
            invokeinterface io.netty.buffer.ByteBufAllocator.buffer:()Lio/netty/buffer/ByteBuf;
            astore 6 /* buffer */
        start local 6 // io.netty.buffer.ByteBuf buffer
         9: .line 60
            aload 4 /* req */
            invokeinterface io.netty.handler.codec.smtp.SmtpRequest.command:()Lio/netty/handler/codec/smtp/SmtpCommand;
            aload 6 /* buffer */
            invokevirtual io.netty.handler.codec.smtp.SmtpCommand.encode:(Lio/netty/buffer/ByteBuf;)V
        10: .line 61
            aload 4 /* req */
            invokeinterface io.netty.handler.codec.smtp.SmtpRequest.parameters:()Ljava/util/List;
            aload 6 /* buffer */
            invokestatic io.netty.handler.codec.smtp.SmtpRequestEncoder.writeParameters:(Ljava/util/List;Lio/netty/buffer/ByteBuf;)V
        11: .line 62
            aload 6 /* buffer */
            sipush 3338
            invokestatic io.netty.buffer.ByteBufUtil.writeShortBE:(Lio/netty/buffer/ByteBuf;I)Lio/netty/buffer/ByteBuf;
            pop
        12: .line 63
            aload 3 /* out */
            aload 6 /* buffer */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        13: .line 64
            iconst_0
            istore 5 /* release */
        14: .line 65
            aload 4 /* req */
            invokeinterface io.netty.handler.codec.smtp.SmtpRequest.command:()Lio/netty/handler/codec/smtp/SmtpCommand;
            invokevirtual io.netty.handler.codec.smtp.SmtpCommand.isContentExpected:()Z
            ifeq 21
        15: .line 66
            aload 0 /* this */
            iconst_1
            putfield io.netty.handler.codec.smtp.SmtpRequestEncoder.contentExpected:Z
        16: .line 68
            goto 21
      StackMap locals: io.netty.handler.codec.smtp.SmtpRequestEncoder io.netty.channel.ChannelHandlerContext java.lang.Object java.util.List io.netty.handler.codec.smtp.SmtpRequest int io.netty.buffer.ByteBuf
      StackMap stack: java.lang.Throwable
        17: astore 7
        18: .line 69
            iload 5 /* release */
            ifeq 20
        19: .line 70
            aload 6 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.release:()Z
            pop
        20: .line 72
      StackMap locals: java.lang.Throwable
      StackMap stack:
            aload 7
            athrow
        21: .line 69
      StackMap locals:
      StackMap stack:
            iload 5 /* release */
            ifeq 23
        22: .line 70
            aload 6 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.release:()Z
            pop
        end local 6 // io.netty.buffer.ByteBuf buffer
        end local 5 // boolean release
        end local 4 // io.netty.handler.codec.smtp.SmtpRequest req
        23: .line 75
      StackMap locals:
      StackMap stack:
            aload 2 /* msg */
            instanceof io.netty.handler.codec.smtp.SmtpContent
            ifeq 31
        24: .line 76
            aload 0 /* this */
            getfield io.netty.handler.codec.smtp.SmtpRequestEncoder.contentExpected:Z
            ifne 26
        25: .line 77
            new java.lang.IllegalStateException
            dup
            ldc "No SmtpContent expected"
            invokespecial java.lang.IllegalStateException.<init>:(Ljava/lang/String;)V
            athrow
        26: .line 79
      StackMap locals:
      StackMap stack:
            aload 2 /* msg */
            checkcast io.netty.handler.codec.smtp.SmtpContent
            invokeinterface io.netty.handler.codec.smtp.SmtpContent.content:()Lio/netty/buffer/ByteBuf;
            astore 4 /* content */
        start local 4 // io.netty.buffer.ByteBuf content
        27: .line 80
            aload 3 /* out */
            aload 4 /* content */
            invokevirtual io.netty.buffer.ByteBuf.retain:()Lio/netty/buffer/ByteBuf;
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        28: .line 81
            aload 2 /* msg */
            instanceof io.netty.handler.codec.smtp.LastSmtpContent
            ifeq 31
        29: .line 82
            aload 3 /* out */
            getstatic io.netty.handler.codec.smtp.SmtpRequestEncoder.DOT_CRLF_BUFFER:Lio/netty/buffer/ByteBuf;
            invokevirtual io.netty.buffer.ByteBuf.retainedDuplicate:()Lio/netty/buffer/ByteBuf;
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        30: .line 83
            aload 0 /* this */
            iconst_0
            putfield io.netty.handler.codec.smtp.SmtpRequestEncoder.contentExpected:Z
        end local 4 // io.netty.buffer.ByteBuf content
        31: .line 86
      StackMap locals:
      StackMap stack:
            return
        end local 3 // java.util.List out
        end local 2 // java.lang.Object msg
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.handler.codec.smtp.SmtpRequestEncoder this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0   32     0     this  Lio/netty/handler/codec/smtp/SmtpRequestEncoder;
            0   32     1      ctx  Lio/netty/channel/ChannelHandlerContext;
            0   32     2      msg  Ljava/lang/Object;
            0   32     3      out  Ljava/util/List<Ljava/lang/Object;>;
            2   23     4      req  Lio/netty/handler/codec/smtp/SmtpRequest;
            8   23     5  release  Z
            9   23     6   buffer  Lio/netty/buffer/ByteBuf;
           27   31     4  content  Lio/netty/buffer/ByteBuf;
      Exception table:
        from    to  target  type
           9    17      17  any
    Exceptions:
      throws java.lang.Exception
    Signature: (Lio/netty/channel/ChannelHandlerContext;Ljava/lang/Object;Ljava/util/List<Ljava/lang/Object;>;)V
    MethodParameters:
      Name  Flags
      ctx   
      msg   
      out   

  private static void writeParameters(java.util.List<java.lang.CharSequence>, io.netty.buffer.ByteBuf);
    descriptor: (Ljava/util/List;Lio/netty/buffer/ByteBuf;)V
    flags: (0x000a) ACC_PRIVATE, ACC_STATIC
    Code:
      stack=3, locals=4, args_size=2
        start local 0 // java.util.List parameters
        start local 1 // io.netty.buffer.ByteBuf out
         0: .line 89
            aload 0 /* parameters */
            invokeinterface java.util.List.isEmpty:()Z
            ifeq 2
         1: .line 90
            return
         2: .line 92
      StackMap locals:
      StackMap stack:
            aload 1 /* out */
            bipush 32
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
            pop
         3: .line 93
            aload 0 /* parameters */
            instanceof java.util.RandomAccess
            ifeq 13
         4: .line 94
            aload 0 /* parameters */
            invokeinterface java.util.List.size:()I
            iconst_1
            isub
            istore 2 /* sizeMinusOne */
        start local 2 // int sizeMinusOne
         5: .line 95
            iconst_0
            istore 3 /* i */
        start local 3 // int i
         6: goto 10
         7: .line 96
      StackMap locals: int int
      StackMap stack:
            aload 1 /* out */
            aload 0 /* parameters */
            iload 3 /* i */
            invokeinterface java.util.List.get:(I)Ljava/lang/Object;
            checkcast java.lang.CharSequence
            invokestatic io.netty.buffer.ByteBufUtil.writeAscii:(Lio/netty/buffer/ByteBuf;Ljava/lang/CharSequence;)I
            pop
         8: .line 97
            aload 1 /* out */
            bipush 32
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
            pop
         9: .line 95
            iinc 3 /* i */ 1
      StackMap locals:
      StackMap stack:
        10: iload 3 /* i */
            iload 2 /* sizeMinusOne */
            if_icmplt 7
        end local 3 // int i
        11: .line 99
            aload 1 /* out */
            aload 0 /* parameters */
            iload 2 /* sizeMinusOne */
            invokeinterface java.util.List.get:(I)Ljava/lang/Object;
            checkcast java.lang.CharSequence
            invokestatic io.netty.buffer.ByteBufUtil.writeAscii:(Lio/netty/buffer/ByteBuf;Ljava/lang/CharSequence;)I
            pop
        end local 2 // int sizeMinusOne
        12: .line 100
            goto 18
        13: .line 101
      StackMap locals:
      StackMap stack:
            aload 0 /* parameters */
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 2 /* params */
        start local 2 // java.util.Iterator params
        14: .line 103
      StackMap locals: java.util.Iterator
      StackMap stack:
            aload 1 /* out */
            aload 2 /* params */
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast java.lang.CharSequence
            invokestatic io.netty.buffer.ByteBufUtil.writeAscii:(Lio/netty/buffer/ByteBuf;Ljava/lang/CharSequence;)I
            pop
        15: .line 104
            aload 2 /* params */
            invokeinterface java.util.Iterator.hasNext:()Z
            ifeq 18
        16: .line 105
            aload 1 /* out */
            bipush 32
            invokevirtual io.netty.buffer.ByteBuf.writeByte:(I)Lio/netty/buffer/ByteBuf;
            pop
        17: .line 102
            goto 14
        end local 2 // java.util.Iterator params
        18: .line 111
      StackMap locals:
      StackMap stack:
            return
        end local 1 // io.netty.buffer.ByteBuf out
        end local 0 // java.util.List parameters
      LocalVariableTable:
        Start  End  Slot          Name  Signature
            0   19     0    parameters  Ljava/util/List<Ljava/lang/CharSequence;>;
            0   19     1           out  Lio/netty/buffer/ByteBuf;
            5   12     2  sizeMinusOne  I
            6   11     3             i  I
           14   18     2        params  Ljava/util/Iterator<Ljava/lang/CharSequence;>;
    Signature: (Ljava/util/List<Ljava/lang/CharSequence;>;Lio/netty/buffer/ByteBuf;)V
    MethodParameters:
            Name  Flags
      parameters  
      out         
}
Signature: Lio/netty/handler/codec/MessageToMessageEncoder<Ljava/lang/Object;>;
SourceFile: "SmtpRequestEncoder.java"